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🧠 LeetCode Solutions Repository

This repository contains my accepted LeetCode solutions for interview preparation & DSA mastery.


👩‍💻 About Me (LeetCode)


📂 Repository Structure

📦 LeetCode-Solutions
┣ 📁 0001 - Two Sum
┃ ┣ 📄 description.md
┃ ┗ 📄 solution.cpp
┣ 📁 0053 - Maximum Subarray
┃ ┣ 📄 description.md
┃ ┗ 📄 solution.cpp
┣ 📁 0128 - Longest Consecutive Sequence
┃ ┣ 📄 description.md
┃ ┗ 📄 solution.cpp
┣ 📁 ...
┗ 📄 README.md

Each folder contains: ✅ Original problem statement
✅ My C++ solution
✅ Clean format for quick revisions


📝 What This Repo Includes

  • Fully accepted C++ solutions
  • Regular commits after practice sessions 🚀
  • Covers All difficulty levels (Easy / Medium / Hard)
  • Placement-oriented preparation

🎯 Goals

  • Reach 800+ solved soon 🎯
  • Focus more on Medium & Hard problems
  • Build interview-ready confidence 👌

🔗 Profile

👉 https://leetcode.com/u/aditisahu12/


⭐ If you are also preparing → Let's connect & grow together!

LeetCode Topics

Array

Problem Name Difficulty
0001-two-sum Easy
0011-container-with-most-water Medium
0015-3sum Medium
0018-4sum Medium
0031-next-permutation Medium
0033-search-in-rotated-sorted-array Medium
0034-find-first-and-last-position-of-element-in-sorted-array Medium
0039-combination-sum Medium
0040-combination-sum-ii Medium
0046-permutations Medium
0047-permutations-ii Medium
0049-group-anagrams Medium
0053-maximum-subarray Medium
0074-search-a-2d-matrix Medium
0075-sort-colors Medium
0078-subsets Medium
0079-word-search Medium
0080-remove-duplicates-from-sorted-array-ii Medium
0090-subsets-ii Medium
0122-best-time-to-buy-and-sell-stock-ii Medium
0128-longest-consecutive-sequence Medium
0130-surrounded-regions Medium
0137-single-number-ii Medium
0152-maximum-product-subarray Medium
0153-find-minimum-in-rotated-sorted-array Medium
0162-find-peak-element Medium
0167-two-sum-ii-input-array-is-sorted Medium
0200-number-of-islands Medium
0215-kth-largest-element-in-an-array Medium
0216-combination-sum-iii Medium
0239-sliding-window-maximum Hard
0240-search-a-2d-matrix-ii Medium
0260-single-number-iii Medium
0275-h-index-ii Medium
0287-find-the-duplicate-number Medium
0318-maximum-product-of-word-lengths Medium
0347-top-k-frequent-elements Medium
0373-find-k-pairs-with-smallest-sums Medium
0378-kth-smallest-element-in-a-sorted-matrix Medium
0399-evaluate-division Medium
0410-split-array-largest-sum Hard
0419-battleships-in-a-board Medium
0475-heaters Medium
0477-total-hamming-distance Medium
0486-predict-the-winner Medium
0496-next-greater-element-i Easy
0503-next-greater-element-ii Medium
0523-continuous-subarray-sum Medium
0525-contiguous-array Medium
0540-single-element-in-a-sorted-array Medium
0560-subarray-sum-equals-k Medium
0628-maximum-product-of-three-numbers Easy
0632-smallest-range-covering-elements-from-k-lists Hard
0654-maximum-binary-tree Medium
0658-find-k-closest-elements Medium
0690-employee-importance Medium
0692-top-k-frequent-words Medium
0695-max-area-of-island Medium
0721-accounts-merge Medium
0739-daily-temperatures Medium
0752-open-the-lock Medium
0769-max-chunks-to-make-sorted Medium
0807-max-increase-to-keep-city-skyline Medium
0809-expressive-words Medium
0825-friends-of-appropriate-ages Medium
0826-most-profit-assigning-work Medium
0839-similar-string-groups Hard
0851-loud-and-rich Medium
0852-peak-index-in-a-mountain-array Medium
0853-car-fleet Medium
0861-score-after-flipping-matrix Medium
0875-koko-eating-bananas Medium
0893-groups-of-special-equivalent-strings Medium
0904-fruit-into-baskets Medium
0918-maximum-sum-circular-subarray Medium
0934-shortest-bridge Medium
0945-minimum-increment-to-make-array-unique Medium
0962-maximum-width-ramp Medium
0969-pancake-sorting Medium
0973-k-closest-points-to-origin Medium
0974-subarray-sums-divisible-by-k Medium
0986-interval-list-intersections Medium
0990-satisfiability-of-equality-equations Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1011-capacity-to-ship-packages-within-d-days Medium
1019-next-greater-node-in-linked-list Medium
1029-two-city-scheduling Medium
1034-coloring-a-border Medium
1053-previous-permutation-with-one-swap Medium
1090-largest-values-from-labels Medium
1110-delete-nodes-and-return-forest Medium
1124-longest-well-performing-interval Medium
1130-minimum-cost-tree-from-leaf-values Medium
1162-as-far-from-land-as-possible Medium
1170-compare-strings-by-frequency-of-the-smallest-character Medium
1186-maximum-subarray-sum-with-one-deletion Medium
1191-k-concatenation-maximum-sum Medium
1202-smallest-string-with-swaps Medium
1248-count-number-of-nice-subarrays Medium
1254-number-of-closed-islands Medium
1260-shift-2d-grid Easy
1267-count-servers-that-communicate Medium
1282-group-the-people-given-the-group-size-they-belong-to Medium
1288-remove-covered-intervals Medium
1296-divide-array-in-sets-of-k-consecutive-numbers Medium
1300-sum-of-mutated-array-closest-to-target Medium
1301-number-of-paths-with-max-score Hard
1331-rank-transform-of-an-array Easy
1338-reduce-array-size-to-the-half Medium
1383-maximum-performance-of-a-team Hard
1406-stone-game-iii Hard
1423-maximum-points-you-can-obtain-from-cards Medium
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium
1442-count-triplets-that-can-form-two-arrays-of-equal-xor Medium
1464-maximum-product-of-two-elements-in-an-array Easy
1471-the-k-strongest-values-in-an-array Medium
1482-minimum-number-of-days-to-make-m-bouquets Medium
1514-path-with-maximum-probability Medium
1524-number-of-sub-arrays-with-odd-sum Medium
1536-minimum-swaps-to-arrange-a-binary-grid Medium
1552-magnetic-force-between-two-balls Medium
1559-detect-cycles-in-2d-grid Medium
1561-maximum-number-of-coins-you-can-get Medium
1574-shortest-subarray-to-be-removed-to-make-array-sorted Medium
1582-special-positions-in-a-binary-matrix Easy
1584-min-cost-to-connect-all-points Medium
1590-make-sum-divisible-by-p Medium
1594-maximum-non-negative-product-in-a-matrix Medium
1627-graph-connectivity-with-threshold Hard
1642-furthest-building-you-can-reach Medium
1664-ways-to-make-a-fair-array Medium
1673-find-the-most-competitive-subsequence Medium
1679-max-number-of-k-sum-pairs Medium
1722-minimize-hamming-distance-after-swap-operations Medium
1732-find-the-highest-altitude Easy
1733-minimum-number-of-people-to-teach Medium
1760-minimum-limit-of-balls-in-a-bag Medium
1765-map-of-highest-peak Medium
1769-minimum-number-of-operations-to-move-all-balls-to-each-box Medium
1775-equal-sum-arrays-with-minimum-number-of-operations Medium
1833-maximum-ice-cream-bars Medium
1846-maximum-element-after-decreasing-and-rearranging Medium
1848-minimum-distance-to-the-target-element Easy
1855-maximum-distance-between-a-pair-of-values Medium
1861-rotating-the-box Medium
1870-minimum-speed-to-arrive-on-time Medium
1898-maximum-number-of-removable-characters Medium
1905-count-sub-islands Medium
1921-eliminate-maximum-number-of-monsters Medium
1926-nearest-exit-from-entrance-in-maze Medium
1944-number-of-visible-people-in-a-queue Hard
1962-remove-stones-to-minimize-the-total Medium
1967-number-of-strings-that-appear-as-substrings-in-word Easy
1979-find-greatest-common-divisor-of-array Easy
1980-find-unique-binary-string Medium
2033-minimum-operations-to-make-a-uni-value-grid Medium
2064-minimized-maximum-of-products-distributed-to-any-store Medium
2091-removing-minimum-and-maximum-from-array Medium
2101-detonate-the-maximum-bombs Medium
2121-intervals-between-identical-elements Medium
2126-destroying-asteroids Medium
2149-rearrange-array-elements-by-sign Medium
2187-minimum-time-to-complete-trips Medium
2196-create-binary-tree-from-descriptions Medium
2208-minimum-operations-to-halve-array-sum Medium
2216-minimum-deletions-to-make-array-beautiful Medium
2226-maximum-candies-allocated-to-k-children Medium
2260-minimum-consecutive-cards-to-pick-up Medium
2352-equal-row-and-column-pairs Medium
2364-count-number-of-bad-pairs Medium
2410-maximum-matching-of-players-with-trainers Medium
2433-find-the-original-array-of-prefix-xor Medium
2462-total-cost-to-hire-k-workers Medium
2482-difference-between-ones-and-zeros-in-row-and-column Medium
2488-count-subarrays-with-median-k Hard
2491-divide-players-into-teams-of-equal-skill Medium
2517-maximum-tastiness-of-candy-basket Medium
2530-maximal-score-after-applying-k-operations Medium
2542-maximum-subsequence-score Medium
2545-sort-the-students-by-their-kth-score Medium
2573-find-the-string-with-lcp Hard
2592-maximize-greatness-of-an-array Medium
2594-minimum-time-to-repair-cars Medium
2610-convert-an-array-into-a-2d-array-with-conditions Medium
2615-sum-of-distances Medium
2616-minimize-the-maximum-difference-of-pairs Medium
2657-find-the-prefix-common-array-of-two-arrays Medium
2658-maximum-number-of-fish-in-a-grid Medium
2779-maximum-beauty-of-an-array-after-applying-operation Medium
2784-check-if-array-is-good Easy
2812-find-the-safest-path-in-a-grid Medium
2861-maximum-number-of-alloys Medium
2895-minimum-processing-time Medium
2906-construct-product-matrix Medium
2946-matrix-similarity-after-cyclic-shifts Easy
2952-minimum-number-of-coins-to-be-added Medium
2958-length-of-longest-subarray-with-at-most-k-frequency Medium
2997-minimum-number-of-operations-to-make-array-xor-equal-to-k Medium
3239-minimum-number-of-flips-to-make-binary-grid-palindromic-i Medium
3286-find-a-safe-walk-through-a-grid Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero Medium
3312-sorted-gcd-pair-queries Hard
3336-find-the-number-of-subsequences-with-equal-gcd Hard
3501-maximize-active-section-with-trade-ii Hard
3513-number-of-unique-xor-triplets-i Medium
3514-number-of-unique-xor-triplets-ii Medium
3532-path-existence-queries-in-a-graph-i Medium
3534-path-existence-queries-in-a-graph-ii Hard
3546-equal-sum-grid-partition-i Medium
3548-equal-sum-grid-partition-ii Hard
3567-minimum-absolute-difference-in-sliding-submatrix Medium
3584-maximum-product-of-first-and-last-elements-of-a-subsequence Medium
3619-count-islands-with-total-value-divisible-by-k Medium
3643-flip-square-submatrix-vertically Easy
3689-maximum-total-subarray-value-i Medium
3731-find-missing-elements Easy
3737-count-subarrays-with-majority-element-i Medium
3740-minimum-distance-between-three-equal-elements-i Easy
3766-minimum-operations-to-make-binary-palindrome Medium
3843-first-element-with-unique-frequency Medium
3867-sum-of-gcd-of-formed-pairs Medium
3876-construct-uniform-parity-array-ii Medium
3895-count-digit-appearances Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium
3905-multi-source-flood-fill Medium
3909-compare-sums-of-bitonic-parts Medium
3910-count-connected-subgraphs-with-even-node-sum Hard
3914-minimum-operations-to-make-array-non-decreasing Medium
3926-count-valid-word-occurrences Medium
3974-maximum-total-sum-of-k-selected-elements Medium
3975-filter-occupied-intervals Medium

Greedy

Problem Name Difficulty
0011-container-with-most-water Medium
0122-best-time-to-buy-and-sell-stock-ii Medium
0316-remove-duplicate-letters Medium
0402-remove-k-digits Medium
0410-split-array-largest-sum Hard
0632-smallest-range-covering-elements-from-k-lists Hard
0649-dota2-senate Medium
0670-maximum-swap Medium
0767-reorganize-string Medium
0769-max-chunks-to-make-sorted Medium
0807-max-increase-to-keep-city-skyline Medium
0826-most-profit-assigning-work Medium
0861-score-after-flipping-matrix Medium
0921-minimum-add-to-make-parentheses-valid Medium
0945-minimum-increment-to-make-array-unique Medium
0969-pancake-sorting Medium
0984-string-without-aaa-or-bbb Medium
1029-two-city-scheduling Medium
1053-previous-permutation-with-one-swap Medium
1081-smallest-subsequence-of-distinct-characters Medium
1090-largest-values-from-labels Medium
1130-minimum-cost-tree-from-leaf-values Medium
1282-group-the-people-given-the-group-size-they-belong-to Medium
1296-divide-array-in-sets-of-k-consecutive-numbers Medium
1338-reduce-array-size-to-the-half Medium
1383-maximum-performance-of-a-team Hard
1400-construct-k-palindrome-strings Medium
1405-longest-happy-string Medium
1433-check-if-a-string-can-break-another-string Medium
1536-minimum-swaps-to-arrange-a-binary-grid Medium
1561-maximum-number-of-coins-you-can-get Medium
1642-furthest-building-you-can-reach Medium
1673-find-the-most-competitive-subsequence Medium
1733-minimum-number-of-people-to-teach Medium
1753-maximum-score-from-removing-stones Medium
1754-largest-merge-of-two-strings Medium
1775-equal-sum-arrays-with-minimum-number-of-operations Medium
1802-maximum-value-at-a-given-index-in-a-bounded-array Medium
1833-maximum-ice-cream-bars Medium
1846-maximum-element-after-decreasing-and-rearranging Medium
1850-minimum-adjacent-swaps-to-reach-the-kth-smallest-number Medium
1921-eliminate-maximum-number-of-monsters Medium
1962-remove-stones-to-minimize-the-total Medium
1963-minimum-number-of-swaps-to-make-the-string-balanced Medium
2064-minimized-maximum-of-products-distributed-to-any-store Medium
2091-removing-minimum-and-maximum-from-array Medium
2126-destroying-asteroids Medium
2182-construct-string-with-repeat-limit Medium
2208-minimum-operations-to-halve-array-sum Medium
2216-minimum-deletions-to-make-array-beautiful Medium
2285-maximum-total-importance-of-roads Medium
2410-maximum-matching-of-players-with-trainers Medium
2517-maximum-tastiness-of-candy-basket Medium
2530-maximal-score-after-applying-k-operations Medium
2542-maximum-subsequence-score Medium
2573-find-the-string-with-lcp Hard
2592-maximize-greatness-of-an-array Medium
2616-minimize-the-maximum-difference-of-pairs Medium
2895-minimum-processing-time Medium
2938-separate-black-and-white-balls Medium
2952-minimum-number-of-coins-to-be-added Medium
3016-minimum-number-of-pushes-to-type-word-ii Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero Medium
3474-lexicographically-smallest-generated-string Hard
3534-path-existence-queries-in-a-graph-ii Hard
3600-maximize-spanning-tree-stability-with-upgrades Hard
3689-maximum-total-subarray-value-i Medium
3914-minimum-operations-to-make-array-non-decreasing Medium
3974-maximum-total-sum-of-k-selected-elements Medium

Matrix

Problem Name Difficulty
0074-search-a-2d-matrix Medium
0079-word-search Medium
0130-surrounded-regions Medium
0200-number-of-islands Medium
0240-search-a-2d-matrix-ii Medium
0378-kth-smallest-element-in-a-sorted-matrix Medium
0419-battleships-in-a-board Medium
0695-max-area-of-island Medium
0807-max-increase-to-keep-city-skyline Medium
0861-score-after-flipping-matrix Medium
0934-shortest-bridge Medium
1034-coloring-a-border Medium
1162-as-far-from-land-as-possible Medium
1254-number-of-closed-islands Medium
1260-shift-2d-grid Easy
1267-count-servers-that-communicate Medium
1301-number-of-paths-with-max-score Hard
1536-minimum-swaps-to-arrange-a-binary-grid Medium
1559-detect-cycles-in-2d-grid Medium
1582-special-positions-in-a-binary-matrix Easy
1594-maximum-non-negative-product-in-a-matrix Medium
1765-map-of-highest-peak Medium
1861-rotating-the-box Medium
1905-count-sub-islands Medium
1926-nearest-exit-from-entrance-in-maze Medium
2033-minimum-operations-to-make-a-uni-value-grid Medium
2352-equal-row-and-column-pairs Medium
2482-difference-between-ones-and-zeros-in-row-and-column Medium
2545-sort-the-students-by-their-kth-score Medium
2573-find-the-string-with-lcp Hard
2658-maximum-number-of-fish-in-a-grid Medium
2812-find-the-safest-path-in-a-grid Medium
2906-construct-product-matrix Medium
2946-matrix-similarity-after-cyclic-shifts Easy
3239-minimum-number-of-flips-to-make-binary-grid-palindromic-i Medium
3286-find-a-safe-walk-through-a-grid Medium
3546-equal-sum-grid-partition-i Medium
3548-equal-sum-grid-partition-ii Hard
3567-minimum-absolute-difference-in-sliding-submatrix Medium
3619-count-islands-with-total-value-divisible-by-k Medium
3643-flip-square-submatrix-vertically Easy
3905-multi-source-flood-fill Medium

String

Problem Name Difficulty
0003-longest-substring-without-repeating-characters Medium
0006-zigzag-conversion Medium
0017-letter-combinations-of-a-phone-number Medium
0049-group-anagrams Medium
0076-minimum-window-substring Hard
0079-word-search Medium
0299-bulls-and-cows Medium
0316-remove-duplicate-letters Medium
0318-maximum-product-of-word-lengths Medium
0394-decode-string Medium
0399-evaluate-division Medium
0402-remove-k-digits Medium
0424-longest-repeating-character-replacement Medium
0433-minimum-genetic-mutation Medium
0451-sort-characters-by-frequency Medium
0481-magical-string Medium
0556-next-greater-element-iii Medium
0567-permutation-in-string Medium
0606-construct-string-from-binary-tree Medium
0649-dota2-senate Medium
0692-top-k-frequent-words Medium
0721-accounts-merge Medium
0752-open-the-lock Medium
0767-reorganize-string Medium
0784-letter-case-permutation Medium
0796-rotate-string Easy
0809-expressive-words Medium
0828-count-unique-characters-of-all-substrings-of-a-given-string Hard
0839-similar-string-groups Hard
0893-groups-of-special-equivalent-strings Medium
0921-minimum-add-to-make-parentheses-valid Medium
0984-string-without-aaa-or-bbb Medium
0988-smallest-string-starting-from-leaf Medium
0990-satisfiability-of-equality-equations Medium
1061-lexicographically-smallest-equivalent-string Medium
1079-letter-tile-possibilities Medium
1081-smallest-subsequence-of-distinct-characters Medium
1170-compare-strings-by-frequency-of-the-smallest-character Medium
1202-smallest-string-with-swaps Medium
1208-get-equal-substrings-within-budget Medium
1209-remove-all-adjacent-duplicates-in-string-ii Medium
1297-maximum-number-of-occurrences-of-a-substring Medium
1358-number-of-substrings-containing-all-three-characters Medium
1400-construct-k-palindrome-strings Medium
1405-longest-happy-string Medium
1433-check-if-a-string-can-break-another-string Medium
1545-find-kth-bit-in-nth-binary-string Medium
1750-minimum-length-of-string-after-deleting-similar-ends Medium
1754-largest-merge-of-two-strings Medium
1769-minimum-number-of-operations-to-move-all-balls-to-each-box Medium
1850-minimum-adjacent-swaps-to-reach-the-kth-smallest-number Medium
1888-minimum-number-of-flips-to-make-the-binary-string-alternating Medium
1898-maximum-number-of-removable-characters Medium
1910-remove-all-occurrences-of-a-substring Medium
1915-number-of-wonderful-substrings Medium
1963-minimum-number-of-swaps-to-make-the-string-balanced Medium
1967-number-of-strings-that-appear-as-substrings-in-word Easy
1980-find-unique-binary-string Medium
2063-vowels-of-all-substrings Medium
2182-construct-string-with-repeat-limit Medium
2262-total-appeal-of-a-string Hard
2337-move-pieces-to-obtain-a-string Medium
2390-removing-stars-from-a-string Medium
2483-minimum-penalty-for-a-shop Medium
2573-find-the-string-with-lcp Hard
2839-check-if-strings-can-be-made-equal-with-operations-i Easy
2938-separate-black-and-white-balls Medium
3016-minimum-number-of-pushes-to-type-word-ii Medium
3211-generate-binary-strings-without-adjacent-zeros Medium
3474-lexicographically-smallest-generated-string Hard
3499-maximize-active-section-with-trade-i Medium
3501-maximize-active-section-with-trade-ii Hard
3517-smallest-palindromic-rearrangement-i Medium
3518-smallest-palindromic-rearrangement-ii Hard
3612-process-string-with-special-operations-i Medium
3756-concatenate-non-zero-digits-and-multiply-by-sum-ii Medium
3863-minimum-operations-to-sort-a-string Medium
3913-sort-vowels-by-frequency Medium
3922-minimum-flips-to-make-binary-string-coherent Medium
3926-count-valid-word-occurrences Medium
3941-password-strength Medium

Recursion

Problem Name Difficulty
0024-swap-nodes-in-pairs Medium
0060-permutation-sequence Hard
0143-reorder-list Medium
0394-decode-string Medium
0486-predict-the-winner Medium
1545-find-kth-bit-in-nth-binary-string Medium
2487-remove-nodes-from-linked-list Medium

Simulation

Problem Name Difficulty
1260-shift-2d-grid Easy
1545-find-kth-bit-in-nth-binary-string Medium
1910-remove-all-occurrences-of-a-substring Medium
2149-rearrange-array-elements-by-sign Medium
2181-merge-nodes-in-between-zeros Medium
2352-equal-row-and-column-pairs Medium
2390-removing-stars-from-a-string Medium
2462-total-cost-to-hire-k-workers Medium
2482-difference-between-ones-and-zeros-in-row-and-column Medium
2946-matrix-similarity-after-cyclic-shifts Easy
3612-process-string-with-special-operations-i Medium
3867-sum-of-gcd-of-formed-pairs Medium

Dynamic Programming

Problem Name Difficulty
0053-maximum-subarray Medium
0122-best-time-to-buy-and-sell-stock-ii Medium
0152-maximum-product-subarray Medium
0410-split-array-largest-sum Hard
0486-predict-the-winner Medium
0788-rotated-digits Medium
0828-count-unique-characters-of-all-substrings-of-a-given-string Hard
0918-maximum-sum-circular-subarray Medium
1130-minimum-cost-tree-from-leaf-values Medium
1162-as-far-from-land-as-possible Medium
1186-maximum-subarray-sum-with-one-deletion Medium
1191-k-concatenation-maximum-sum Medium
1301-number-of-paths-with-max-score Hard
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance Medium
1372-longest-zigzag-path-in-a-binary-tree Medium
1406-stone-game-iii Hard
1524-number-of-sub-arrays-with-odd-sum Medium
1594-maximum-non-negative-product-in-a-matrix Medium
1888-minimum-number-of-flips-to-make-the-binary-string-alternating Medium
2063-vowels-of-all-substrings Medium
2262-total-appeal-of-a-string Hard
2573-find-the-string-with-lcp Hard
2616-minimize-the-maximum-difference-of-pairs Medium
3129-find-all-possible-stable-binary-arrays-i Medium
3130-find-all-possible-stable-binary-arrays-ii Hard
3336-find-the-number-of-subsequences-with-equal-gcd Hard
3534-path-existence-queries-in-a-graph-ii Hard
3857-minimum-cost-to-split-into-ones Medium

Sliding Window

Problem Name Difficulty
0003-longest-substring-without-repeating-characters Medium
0076-minimum-window-substring Hard
0239-sliding-window-maximum Hard
0424-longest-repeating-character-replacement Medium
0567-permutation-in-string Medium
0632-smallest-range-covering-elements-from-k-lists Hard
0658-find-k-closest-elements Medium
0904-fruit-into-baskets Medium
1208-get-equal-substrings-within-budget Medium
1248-count-number-of-nice-subarrays Medium
1297-maximum-number-of-occurrences-of-a-substring Medium
1358-number-of-substrings-containing-all-three-characters Medium
1423-maximum-points-you-can-obtain-from-cards Medium
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium
1888-minimum-number-of-flips-to-make-the-binary-string-alternating Medium
2260-minimum-consecutive-cards-to-pick-up Medium
2779-maximum-beauty-of-an-array-after-applying-operation Medium
2958-length-of-longest-subarray-with-at-most-k-frequency Medium

Hash Table

Problem Name Difficulty
0001-two-sum Easy
0003-longest-substring-without-repeating-characters Medium
0017-letter-combinations-of-a-phone-number Medium
0049-group-anagrams Medium
0076-minimum-window-substring Hard
0128-longest-consecutive-sequence Medium
0133-clone-graph Medium
0299-bulls-and-cows Medium
0347-top-k-frequent-elements Medium
0424-longest-repeating-character-replacement Medium
0433-minimum-genetic-mutation Medium
0451-sort-characters-by-frequency Medium
0496-next-greater-element-i Easy
0508-most-frequent-subtree-sum Medium
0523-continuous-subarray-sum Medium
0525-contiguous-array Medium
0560-subarray-sum-equals-k Medium
0567-permutation-in-string Medium
0632-smallest-range-covering-elements-from-k-lists Hard
0652-find-duplicate-subtrees Medium
0690-employee-importance Medium
0692-top-k-frequent-words Medium
0721-accounts-merge Medium
0752-open-the-lock Medium
0767-reorganize-string Medium
0828-count-unique-characters-of-all-substrings-of-a-given-string Hard
0839-similar-string-groups Hard
0863-all-nodes-distance-k-in-binary-tree Medium
0893-groups-of-special-equivalent-strings Medium
0904-fruit-into-baskets Medium
0974-subarray-sums-divisible-by-k Medium
1079-letter-tile-possibilities Medium
1090-largest-values-from-labels Medium
1110-delete-nodes-and-return-forest Medium
1124-longest-well-performing-interval Medium
1170-compare-strings-by-frequency-of-the-smallest-character Medium
1202-smallest-string-with-swaps Medium
1248-count-number-of-nice-subarrays Medium
1282-group-the-people-given-the-group-size-they-belong-to Medium
1296-divide-array-in-sets-of-k-consecutive-numbers Medium
1297-maximum-number-of-occurrences-of-a-substring Medium
1331-rank-transform-of-an-array Easy
1338-reduce-array-size-to-the-half Medium
1358-number-of-substrings-containing-all-three-characters Medium
1400-construct-k-palindrome-strings Medium
1442-count-triplets-that-can-form-two-arrays-of-equal-xor Medium
1519-number-of-nodes-in-the-sub-tree-with-the-same-label Medium
1590-make-sum-divisible-by-p Medium
1679-max-number-of-k-sum-pairs Medium
1733-minimum-number-of-people-to-teach Medium
1775-equal-sum-arrays-with-minimum-number-of-operations Medium
1915-number-of-wonderful-substrings Medium
1980-find-unique-binary-string Medium
2121-intervals-between-identical-elements Medium
2182-construct-string-with-repeat-limit Medium
2196-create-binary-tree-from-descriptions Medium
2260-minimum-consecutive-cards-to-pick-up Medium
2262-total-appeal-of-a-string Hard
2336-smallest-number-in-infinite-set Medium
2352-equal-row-and-column-pairs Medium
2364-count-number-of-bad-pairs Medium
2385-amount-of-time-for-binary-tree-to-be-infected Medium
2488-count-subarrays-with-median-k Hard
2491-divide-players-into-teams-of-equal-skill Medium
2610-convert-an-array-into-a-2d-array-with-conditions Medium
2615-sum-of-distances Medium
2657-find-the-prefix-common-array-of-two-arrays Medium
2784-check-if-array-is-good Easy
2958-length-of-longest-subarray-with-at-most-k-frequency Medium
3016-minimum-number-of-pushes-to-type-word-ii Medium
3312-sorted-gcd-pair-queries Hard
3518-smallest-palindromic-rearrangement-ii Hard
3532-path-existence-queries-in-a-graph-i Medium
3548-equal-sum-grid-partition-ii Hard
3731-find-missing-elements Easy
3737-count-subarrays-with-majority-element-i Medium
3740-minimum-distance-between-three-equal-elements-i Easy
3843-first-element-with-unique-frequency Medium
3926-count-valid-word-occurrences Medium
3941-password-strength Medium

Backtracking

Problem Name Difficulty
0017-letter-combinations-of-a-phone-number Medium
0039-combination-sum Medium
0040-combination-sum-ii Medium
0046-permutations Medium
0047-permutations-ii Medium
0077-combinations Medium
0078-subsets Medium
0079-word-search Medium
0090-subsets-ii Medium
0113-path-sum-ii Medium
0216-combination-sum-iii Medium
0784-letter-case-permutation Medium
0797-all-paths-from-source-to-target Medium
0988-smallest-string-starting-from-leaf Medium
1079-letter-tile-possibilities Medium
1980-find-unique-binary-string Medium
3211-generate-binary-strings-without-adjacent-zeros Medium

Prefix Sum

Problem Name Difficulty
0410-split-array-largest-sum Hard
0523-continuous-subarray-sum Medium
0525-contiguous-array Medium
0560-subarray-sum-equals-k Medium
0974-subarray-sums-divisible-by-k Medium
1124-longest-well-performing-interval Medium
1208-get-equal-substrings-within-budget Medium
1248-count-number-of-nice-subarrays Medium
1423-maximum-points-you-can-obtain-from-cards Medium
1442-count-triplets-that-can-form-two-arrays-of-equal-xor Medium
1524-number-of-sub-arrays-with-odd-sum Medium
1590-make-sum-divisible-by-p Medium
1664-ways-to-make-a-fair-array Medium
1732-find-the-highest-altitude Easy
1769-minimum-number-of-operations-to-move-all-balls-to-each-box Medium
1915-number-of-wonderful-substrings Medium
2121-intervals-between-identical-elements Medium
2483-minimum-penalty-for-a-shop Medium
2488-count-subarrays-with-median-k Hard
2615-sum-of-distances Medium
2906-construct-product-matrix Medium
3129-find-all-possible-stable-binary-arrays-i Medium
3130-find-all-possible-stable-binary-arrays-ii Hard
3312-sorted-gcd-pair-queries Hard
3546-equal-sum-grid-partition-i Medium
3548-equal-sum-grid-partition-ii Hard
3737-count-subarrays-with-majority-element-i Medium
3756-concatenate-non-zero-digits-and-multiply-by-sum-ii Medium

Two Pointers

Problem Name Difficulty
0011-container-with-most-water Medium
0015-3sum Medium
0018-4sum Medium
0031-next-permutation Medium
0075-sort-colors Medium
0080-remove-duplicates-from-sorted-array-ii Medium
0082-remove-duplicates-from-sorted-list-ii Medium
0086-partition-list Medium
0143-reorder-list Medium
0167-two-sum-ii-input-array-is-sorted Medium
0287-find-the-duplicate-number Medium
0295-find-median-from-data-stream Hard
0475-heaters Medium
0481-magical-string Medium
0556-next-greater-element-iii Medium
0567-permutation-in-string Medium
0658-find-k-closest-elements Medium
0809-expressive-words Medium
0825-friends-of-appropriate-ages Medium
0826-most-profit-assigning-work Medium
0962-maximum-width-ramp Medium
0969-pancake-sorting Medium
0986-interval-list-intersections Medium
1471-the-k-strongest-values-in-an-array Medium
1574-shortest-subarray-to-be-removed-to-make-array-sorted Medium
1679-max-number-of-k-sum-pairs Medium
1721-swapping-nodes-in-a-linked-list Medium
1750-minimum-length-of-string-after-deleting-similar-ends Medium
1754-largest-merge-of-two-strings Medium
1850-minimum-adjacent-swaps-to-reach-the-kth-smallest-number Medium
1855-maximum-distance-between-a-pair-of-values Medium
1861-rotating-the-box Medium
1898-maximum-number-of-removable-characters Medium
1963-minimum-number-of-swaps-to-make-the-string-balanced Medium
2095-delete-the-middle-node-of-a-linked-list Medium
2130-maximum-twin-sum-of-a-linked-list Medium
2149-rearrange-array-elements-by-sign Medium
2337-move-pieces-to-obtain-a-string Medium
2410-maximum-matching-of-players-with-trainers Medium
2462-total-cost-to-hire-k-workers Medium
2491-divide-players-into-teams-of-equal-skill Medium
2592-maximize-greatness-of-an-array Medium
2938-separate-black-and-white-balls Medium
3239-minimum-number-of-flips-to-make-binary-grid-palindromic-i Medium
3534-path-existence-queries-in-a-graph-ii Hard
3584-maximum-product-of-first-and-last-elements-of-a-subsequence Medium
3643-flip-square-submatrix-vertically Easy
3722-lexicographically-smallest-string-after-reverse Medium
3766-minimum-operations-to-make-binary-palindrome Medium
3867-sum-of-gcd-of-formed-pairs Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium

Sorting

Problem Name Difficulty
0015-3sum Medium
0018-4sum Medium
0047-permutations-ii Medium
0049-group-anagrams Medium
0075-sort-colors Medium
0215-kth-largest-element-in-an-array Medium
0295-find-median-from-data-stream Hard
0347-top-k-frequent-elements Medium
0378-kth-smallest-element-in-a-sorted-matrix Medium
0451-sort-characters-by-frequency Medium
0475-heaters Medium
0628-maximum-product-of-three-numbers Easy
0632-smallest-range-covering-elements-from-k-lists Hard
0658-find-k-closest-elements Medium
0692-top-k-frequent-words Medium
0721-accounts-merge Medium
0767-reorganize-string Medium
0769-max-chunks-to-make-sorted Medium
0825-friends-of-appropriate-ages Medium
0826-most-profit-assigning-work Medium
0853-car-fleet Medium
0893-groups-of-special-equivalent-strings Medium
0945-minimum-increment-to-make-array-unique Medium
0969-pancake-sorting Medium
0973-k-closest-points-to-origin Medium
1029-two-city-scheduling Medium
1090-largest-values-from-labels Medium
1170-compare-strings-by-frequency-of-the-smallest-character Medium
1202-smallest-string-with-swaps Medium
1288-remove-covered-intervals Medium
1296-divide-array-in-sets-of-k-consecutive-numbers Medium
1300-sum-of-mutated-array-closest-to-target Medium
1305-all-elements-in-two-binary-search-trees Medium
1331-rank-transform-of-an-array Easy
1338-reduce-array-size-to-the-half Medium
1383-maximum-performance-of-a-team Hard
1433-check-if-a-string-can-break-another-string Medium
1464-maximum-product-of-two-elements-in-an-array Easy
1471-the-k-strongest-values-in-an-array Medium
1552-magnetic-force-between-two-balls Medium
1561-maximum-number-of-coins-you-can-get Medium
1679-max-number-of-k-sum-pairs Medium
1833-maximum-ice-cream-bars Medium
1846-maximum-element-after-decreasing-and-rearranging Medium
1921-eliminate-maximum-number-of-monsters Medium
2033-minimum-operations-to-make-a-uni-value-grid Medium
2126-destroying-asteroids Medium
2285-maximum-total-importance-of-roads Medium
2410-maximum-matching-of-players-with-trainers Medium
2491-divide-players-into-teams-of-equal-skill Medium
2517-maximum-tastiness-of-candy-basket Medium
2542-maximum-subsequence-score Medium
2545-sort-the-students-by-their-kth-score Medium
2592-maximize-greatness-of-an-array Medium
2616-minimize-the-maximum-difference-of-pairs Medium
2779-maximum-beauty-of-an-array-after-applying-operation Medium
2784-check-if-array-is-good Easy
2895-minimum-processing-time Medium
2952-minimum-number-of-coins-to-be-added Medium
3016-minimum-number-of-pushes-to-type-word-ii Medium
3517-smallest-palindromic-rearrangement-i Medium
3534-path-existence-queries-in-a-graph-ii Hard
3536-maximum-product-of-two-digits Easy
3567-minimum-absolute-difference-in-sliding-submatrix Medium
3608-minimum-time-for-k-connected-components Medium
3731-find-missing-elements Easy
3867-sum-of-gcd-of-formed-pairs Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium
3913-sort-vowels-by-frequency Medium
3974-maximum-total-sum-of-k-selected-elements Medium
3975-filter-occupied-intervals Medium

Binary Search

Problem Name Difficulty
0033-search-in-rotated-sorted-array Medium
0034-find-first-and-last-position-of-element-in-sorted-array Medium
0074-search-a-2d-matrix Medium
0153-find-minimum-in-rotated-sorted-array Medium
0162-find-peak-element Medium
0167-two-sum-ii-input-array-is-sorted Medium
0240-search-a-2d-matrix-ii Medium
0275-h-index-ii Medium
0287-find-the-duplicate-number Medium
0378-kth-smallest-element-in-a-sorted-matrix Medium
0410-split-array-largest-sum Hard
0475-heaters Medium
0540-single-element-in-a-sorted-array Medium
0658-find-k-closest-elements Medium
0825-friends-of-appropriate-ages Medium
0826-most-profit-assigning-work Medium
0852-peak-index-in-a-mountain-array Medium
0875-koko-eating-bananas Medium
1011-capacity-to-ship-packages-within-d-days Medium
1170-compare-strings-by-frequency-of-the-smallest-character Medium
1208-get-equal-substrings-within-budget Medium
1300-sum-of-mutated-array-closest-to-target Medium
1482-minimum-number-of-days-to-make-m-bouquets Medium
1552-magnetic-force-between-two-balls Medium
1574-shortest-subarray-to-be-removed-to-make-array-sorted Medium
1760-minimum-limit-of-balls-in-a-bag Medium
1802-maximum-value-at-a-given-index-in-a-bounded-array Medium
1855-maximum-distance-between-a-pair-of-values Medium
1870-minimum-speed-to-arrive-on-time Medium
1898-maximum-number-of-removable-characters Medium
2064-minimized-maximum-of-products-distributed-to-any-store Medium
2187-minimum-time-to-complete-trips Medium
2226-maximum-candies-allocated-to-k-children Medium
2517-maximum-tastiness-of-candy-basket Medium
2594-minimum-time-to-repair-cars Medium
2616-minimize-the-maximum-difference-of-pairs Medium
2779-maximum-beauty-of-an-array-after-applying-operation Medium
2812-find-the-safest-path-in-a-grid Medium
2861-maximum-number-of-alloys Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero Medium
3312-sorted-gcd-pair-queries Hard
3501-maximize-active-section-with-trade-ii Hard
3532-path-existence-queries-in-a-graph-i Medium
3534-path-existence-queries-in-a-graph-ii Hard
3600-maximize-spanning-tree-stability-with-upgrades Hard
3608-minimum-time-for-k-connected-components Medium
3722-lexicographically-smallest-string-after-reverse Medium
3766-minimum-operations-to-make-binary-palindrome Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium

Bit Manipulation

Problem Name Difficulty
0078-subsets Medium
0090-subsets-ii Medium
0137-single-number-ii Medium
0201-bitwise-and-of-numbers-range Medium
0260-single-number-iii Medium
0287-find-the-duplicate-number Medium
0318-maximum-product-of-word-lengths Medium
0477-total-hamming-distance Medium
0784-letter-case-permutation Medium
0861-score-after-flipping-matrix Medium
1009-complement-of-base-10-integer Easy
1318-minimum-flips-to-make-a-or-b-equal-to-c Medium
1442-count-triplets-that-can-form-two-arrays-of-equal-xor Medium
1457-pseudo-palindromic-paths-in-a-binary-tree Medium
1915-number-of-wonderful-substrings Medium
2433-find-the-original-array-of-prefix-xor Medium
2657-find-the-prefix-common-array-of-two-arrays Medium
2997-minimum-number-of-operations-to-make-array-xor-equal-to-k Medium
3211-generate-binary-strings-without-adjacent-zeros Medium
3513-number-of-unique-xor-triplets-i Medium
3514-number-of-unique-xor-triplets-ii Medium
3534-path-existence-queries-in-a-graph-ii Hard
3766-minimum-operations-to-make-binary-palindrome Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Counting

Problem Name Difficulty
0299-bulls-and-cows Medium
0347-top-k-frequent-elements Medium
0451-sort-characters-by-frequency Medium
0692-top-k-frequent-words Medium
0767-reorganize-string Medium
0945-minimum-increment-to-make-array-unique Medium
1079-letter-tile-possibilities Medium
1090-largest-values-from-labels Medium
1267-count-servers-that-communicate Medium
1400-construct-k-palindrome-strings Medium
1519-number-of-nodes-in-the-sub-tree-with-the-same-label Medium
1775-equal-sum-arrays-with-minimum-number-of-operations Medium
2182-construct-string-with-repeat-limit Medium
2364-count-number-of-bad-pairs Medium
3016-minimum-number-of-pushes-to-type-word-ii Medium
3312-sorted-gcd-pair-queries Hard
3518-smallest-palindromic-rearrangement-ii Hard
3737-count-subarrays-with-majority-element-i Medium
3843-first-element-with-unique-frequency Medium
3913-sort-vowels-by-frequency Medium
3926-count-valid-word-occurrences Medium

Divide and Conquer

Problem Name Difficulty
0023-merge-k-sorted-lists Hard
0053-maximum-subarray Medium
0215-kth-largest-element-in-an-array Medium
0240-search-a-2d-matrix-ii Medium
0347-top-k-frequent-elements Medium
0654-maximum-binary-tree Medium
0918-maximum-sum-circular-subarray Medium
0973-k-closest-points-to-origin Medium
3737-count-subarrays-with-majority-element-i Medium

Heap (Priority Queue)

Problem Name Difficulty
0023-merge-k-sorted-lists Hard
0215-kth-largest-element-in-an-array Medium
0239-sliding-window-maximum Hard
0295-find-median-from-data-stream Hard
0347-top-k-frequent-elements Medium
0373-find-k-pairs-with-smallest-sums Medium
0378-kth-smallest-element-in-a-sorted-matrix Medium
0451-sort-characters-by-frequency Medium
0632-smallest-range-covering-elements-from-k-lists Hard
0658-find-k-closest-elements Medium
0692-top-k-frequent-words Medium
0767-reorganize-string Medium
0973-k-closest-points-to-origin Medium
1338-reduce-array-size-to-the-half Medium
1383-maximum-performance-of-a-team Hard
1405-longest-happy-string Medium
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium
1464-maximum-product-of-two-elements-in-an-array Easy
1514-path-with-maximum-probability Medium
1642-furthest-building-you-can-reach Medium
1753-maximum-score-from-removing-stones Medium
1962-remove-stones-to-minimize-the-total Medium
2182-construct-string-with-repeat-limit Medium
2208-minimum-operations-to-halve-array-sum Medium
2285-maximum-total-importance-of-roads Medium
2336-smallest-number-in-infinite-set Medium
2462-total-cost-to-hire-k-workers Medium
2530-maximal-score-after-applying-k-operations Medium
2542-maximum-subsequence-score Medium
2812-find-the-safest-path-in-a-grid Medium
3286-find-a-safe-walk-through-a-grid Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero Medium

Math

Problem Name Difficulty
0060-permutation-sequence Hard
0477-total-hamming-distance Medium
0486-predict-the-winner Medium
0523-continuous-subarray-sum Medium
0556-next-greater-element-iii Medium
0628-maximum-product-of-three-numbers Easy
0670-maximum-swap Medium
0788-rotated-digits Medium
0973-k-closest-points-to-origin Medium
1248-count-number-of-nice-subarrays Medium
1344-angle-between-hands-of-a-clock Medium
1406-stone-game-iii Hard
1442-count-triplets-that-can-form-two-arrays-of-equal-xor Medium
1524-number-of-sub-arrays-with-odd-sum Medium
1561-maximum-number-of-coins-you-can-get Medium
1622-fancy-sequence Hard
1627-graph-connectivity-with-threshold Hard
1753-maximum-score-from-removing-stones Medium
1802-maximum-value-at-a-given-index-in-a-bounded-array Medium
1979-find-greatest-common-divisor-of-array Easy
2033-minimum-operations-to-make-a-uni-value-grid Medium
2063-vowels-of-all-substrings Medium
2101-detonate-the-maximum-bombs Medium
2364-count-number-of-bad-pairs Medium
2807-insert-greatest-common-divisors-in-linked-list Medium
2946-matrix-similarity-after-cyclic-shifts Easy
3296-minimum-number-of-seconds-to-make-mountain-height-zero Medium
3312-sorted-gcd-pair-queries Hard
3336-find-the-number-of-subsequences-with-equal-gcd Hard
3513-number-of-unique-xor-triplets-i Medium
3514-number-of-unique-xor-triplets-ii Medium
3518-smallest-palindromic-rearrangement-ii Hard
3536-maximum-product-of-two-digits Easy
3658-gcd-of-odd-and-even-sums Easy
3754-concatenate-non-zero-digits-and-multiply-by-sum-i Easy
3756-concatenate-non-zero-digits-and-multiply-by-sum-ii Medium
3857-minimum-cost-to-split-into-ones Medium
3867-sum-of-gcd-of-formed-pairs Medium
3871-count-commas-in-range-ii Medium
3876-construct-uniform-parity-array-ii Medium
3895-count-digit-appearances Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium

Union-Find

Problem Name Difficulty
0128-longest-consecutive-sequence Medium
0130-surrounded-regions Medium
0200-number-of-islands Medium
0399-evaluate-division Medium
0547-number-of-provinces Medium
0684-redundant-connection Medium
0695-max-area-of-island Medium
0721-accounts-merge Medium
0839-similar-string-groups Hard
0990-satisfiability-of-equality-equations Medium
1061-lexicographically-smallest-equivalent-string Medium
1202-smallest-string-with-swaps Medium
1254-number-of-closed-islands Medium
1267-count-servers-that-communicate Medium
1319-number-of-operations-to-make-network-connected Medium
1559-detect-cycles-in-2d-grid Medium
1579-remove-max-number-of-edges-to-keep-graph-fully-traversable Hard
1584-min-cost-to-connect-all-points Medium
1627-graph-connectivity-with-threshold Hard
1722-minimize-hamming-distance-after-swap-operations Medium
1905-count-sub-islands Medium
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph Medium
2492-minimum-score-of-a-path-between-two-cities Medium
2573-find-the-string-with-lcp Hard
2658-maximum-number-of-fish-in-a-grid Medium
2685-count-the-number-of-complete-components Medium
2812-find-the-safest-path-in-a-grid Medium
3532-path-existence-queries-in-a-graph-i Medium
3600-maximize-spanning-tree-stability-with-upgrades Hard
3608-minimum-time-for-k-connected-components Medium
3619-count-islands-with-total-value-divisible-by-k Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Graph Theory

Problem Name Difficulty
0133-clone-graph Medium
0207-course-schedule Medium
0210-course-schedule-ii Medium
0310-minimum-height-trees Medium
0399-evaluate-division Medium
0547-number-of-provinces Medium
0684-redundant-connection Medium
0797-all-paths-from-source-to-target Medium
0802-find-eventual-safe-states Medium
0841-keys-and-rooms Medium
0851-loud-and-rich Medium
0990-satisfiability-of-equality-equations Medium
1129-shortest-path-with-alternating-colors Medium
1319-number-of-operations-to-make-network-connected Medium
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance Medium
1462-course-schedule-iv Medium
1514-path-with-maximum-probability Medium
1557-minimum-number-of-vertices-to-reach-all-nodes Medium
1579-remove-max-number-of-edges-to-keep-graph-fully-traversable Hard
1584-min-cost-to-connect-all-points Medium
1615-maximal-network-rank Medium
2101-detonate-the-maximum-bombs Medium
2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph Medium
2285-maximum-total-importance-of-roads Medium
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph Medium
2492-minimum-score-of-a-path-between-two-cities Medium
2685-count-the-number-of-complete-components Medium
3286-find-a-safe-walk-through-a-grid Medium
3532-path-existence-queries-in-a-graph-i Medium
3534-path-existence-queries-in-a-graph-ii Hard
3600-maximize-spanning-tree-stability-with-upgrades Hard
3608-minimum-time-for-k-connected-components Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Minimum Spanning Tree

Problem Name Difficulty
1584-min-cost-to-connect-all-points Medium
3600-maximize-spanning-tree-stability-with-upgrades Hard

Design

Problem Name Difficulty
0173-binary-search-tree-iterator Medium
0295-find-median-from-data-stream Hard
0901-online-stock-span Medium
1622-fancy-sequence Hard
2336-smallest-number-in-infinite-set Medium

Segment Tree

Problem Name Difficulty
1622-fancy-sequence Hard
3501-maximize-active-section-with-trade-ii Hard
3737-count-subarrays-with-majority-element-i Medium

Queue

Problem Name Difficulty
0239-sliding-window-maximum Hard
0649-dota2-senate Medium
0918-maximum-sum-circular-subarray Medium
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium

Ordered Set

Problem Name Difficulty
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium
2336-smallest-number-in-infinite-set Medium

Monotonic Queue

Problem Name Difficulty
0239-sliding-window-maximum Hard
0918-maximum-sum-circular-subarray Medium
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit Medium

Stack

Problem Name Difficulty
0114-flatten-binary-tree-to-linked-list Medium
0143-reorder-list Medium
0173-binary-search-tree-iterator Medium
0316-remove-duplicate-letters Medium
0394-decode-string Medium
0402-remove-k-digits Medium
0496-next-greater-element-i Easy
0503-next-greater-element-ii Medium
0654-maximum-binary-tree Medium
0739-daily-temperatures Medium
0769-max-chunks-to-make-sorted Medium
0853-car-fleet Medium
0901-online-stock-span Medium
0921-minimum-add-to-make-parentheses-valid Medium
0962-maximum-width-ramp Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1019-next-greater-node-in-linked-list Medium
1081-smallest-subsequence-of-distinct-characters Medium
1124-longest-well-performing-interval Medium
1130-minimum-cost-tree-from-leaf-values Medium
1209-remove-all-adjacent-duplicates-in-string-ii Medium
1574-shortest-subarray-to-be-removed-to-make-array-sorted Medium
1673-find-the-most-competitive-subsequence Medium
1910-remove-all-occurrences-of-a-substring Medium
1944-number-of-visible-people-in-a-queue Hard
1963-minimum-number-of-swaps-to-make-the-string-balanced Medium
2130-maximum-twin-sum-of-a-linked-list Medium
2216-minimum-deletions-to-make-array-beautiful Medium
2390-removing-stars-from-a-string Medium
2487-remove-nodes-from-linked-list Medium

Monotonic Stack

Problem Name Difficulty
0316-remove-duplicate-letters Medium
0402-remove-k-digits Medium
0496-next-greater-element-i Easy
0503-next-greater-element-ii Medium
0654-maximum-binary-tree Medium
0739-daily-temperatures Medium
0769-max-chunks-to-make-sorted Medium
0853-car-fleet Medium
0901-online-stock-span Medium
0962-maximum-width-ramp Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1019-next-greater-node-in-linked-list Medium
1081-smallest-subsequence-of-distinct-characters Medium
1124-longest-well-performing-interval Medium
1130-minimum-cost-tree-from-leaf-values Medium
1574-shortest-subarray-to-be-removed-to-make-array-sorted Medium
1673-find-the-most-competitive-subsequence Medium
1944-number-of-visible-people-in-a-queue Hard
2487-remove-nodes-from-linked-list Medium

Enumeration

Problem Name Difficulty
1291-sequential-digits Medium
3499-maximize-active-section-with-trade-i Medium
3514-number-of-unique-xor-triplets-ii Medium
3546-equal-sum-grid-partition-i Medium
3548-equal-sum-grid-partition-ii Hard
3722-lexicographically-smallest-string-after-reverse Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Shortest Path

Problem Name Difficulty
0399-evaluate-division Medium
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance Medium
1514-path-with-maximum-probability Medium
3286-find-a-safe-walk-through-a-grid Medium

Depth-First Search

Problem Name Difficulty
0079-word-search Medium
0098-validate-binary-search-tree Medium
0104-maximum-depth-of-binary-tree Easy
0113-path-sum-ii Medium
0114-flatten-binary-tree-to-linked-list Medium
0116-populating-next-right-pointers-in-each-node Medium
0117-populating-next-right-pointers-in-each-node-ii Medium
0129-sum-root-to-leaf-numbers Medium
0130-surrounded-regions Medium
0133-clone-graph Medium
0199-binary-tree-right-side-view Medium
0200-number-of-islands Medium
0207-course-schedule Medium
0210-course-schedule-ii Medium
0230-kth-smallest-element-in-a-bst Medium
0236-lowest-common-ancestor-of-a-binary-tree Medium
0310-minimum-height-trees Medium
0399-evaluate-division Medium
0419-battleships-in-a-board Medium
0437-path-sum-iii Medium
0508-most-frequent-subtree-sum Medium
0513-find-bottom-left-tree-value Medium
0538-convert-bst-to-greater-tree Medium
0547-number-of-provinces Medium
0606-construct-string-from-binary-tree Medium
0623-add-one-row-to-tree Medium
0652-find-duplicate-subtrees Medium
0662-maximum-width-of-binary-tree Medium
0684-redundant-connection Medium
0690-employee-importance Medium
0695-max-area-of-island Medium
0721-accounts-merge Medium
0797-all-paths-from-source-to-target Medium
0802-find-eventual-safe-states Medium
0839-similar-string-groups Hard
0841-keys-and-rooms Medium
0851-loud-and-rich Medium
0863-all-nodes-distance-k-in-binary-tree Medium
0934-shortest-bridge Medium
0951-flip-equivalent-binary-trees Medium
0979-distribute-coins-in-binary-tree Medium
0988-smallest-string-starting-from-leaf Medium
1026-maximum-difference-between-node-and-ancestor Medium
1034-coloring-a-border Medium
1038-binary-search-tree-to-greater-sum-tree Medium
1110-delete-nodes-and-return-forest Medium
1202-smallest-string-with-swaps Medium
1254-number-of-closed-islands Medium
1267-count-servers-that-communicate Medium
1302-deepest-leaves-sum Medium
1305-all-elements-in-two-binary-search-trees Medium
1315-sum-of-nodes-with-even-valued-grandparent Medium
1319-number-of-operations-to-make-network-connected Medium
1325-delete-leaves-with-a-given-value Medium
1367-linked-list-in-binary-tree Medium
1372-longest-zigzag-path-in-a-binary-tree Medium
1376-time-needed-to-inform-all-employees Medium
1448-count-good-nodes-in-binary-tree Medium
1457-pseudo-palindromic-paths-in-a-binary-tree Medium
1462-course-schedule-iv Medium
1519-number-of-nodes-in-the-sub-tree-with-the-same-label Medium
1530-number-of-good-leaf-nodes-pairs Medium
1559-detect-cycles-in-2d-grid Medium
1722-minimize-hamming-distance-after-swap-operations Medium
1905-count-sub-islands Medium
2101-detonate-the-maximum-bombs Medium
2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph Medium
2265-count-nodes-equal-to-average-of-subtree Medium
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph Medium
2385-amount-of-time-for-binary-tree-to-be-infected Medium
2415-reverse-odd-levels-of-binary-tree Medium
2492-minimum-score-of-a-path-between-two-cities Medium
2658-maximum-number-of-fish-in-a-grid Medium
2685-count-the-number-of-complete-components Medium
3619-count-islands-with-total-value-divisible-by-k Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Breadth-First Search

Problem Name Difficulty
0104-maximum-depth-of-binary-tree Easy
0107-binary-tree-level-order-traversal-ii Medium
0116-populating-next-right-pointers-in-each-node Medium
0117-populating-next-right-pointers-in-each-node-ii Medium
0130-surrounded-regions Medium
0133-clone-graph Medium
0199-binary-tree-right-side-view Medium
0200-number-of-islands Medium
0207-course-schedule Medium
0210-course-schedule-ii Medium
0310-minimum-height-trees Medium
0399-evaluate-division Medium
0433-minimum-genetic-mutation Medium
0513-find-bottom-left-tree-value Medium
0547-number-of-provinces Medium
0623-add-one-row-to-tree Medium
0662-maximum-width-of-binary-tree Medium
0684-redundant-connection Medium
0690-employee-importance Medium
0695-max-area-of-island Medium
0721-accounts-merge Medium
0752-open-the-lock Medium
0797-all-paths-from-source-to-target Medium
0802-find-eventual-safe-states Medium
0839-similar-string-groups Hard
0841-keys-and-rooms Medium
0863-all-nodes-distance-k-in-binary-tree Medium
0934-shortest-bridge Medium
0958-check-completeness-of-a-binary-tree Medium
1034-coloring-a-border Medium
1129-shortest-path-with-alternating-colors Medium
1162-as-far-from-land-as-possible Medium
1202-smallest-string-with-swaps Medium
1254-number-of-closed-islands Medium
1267-count-servers-that-communicate Medium
1302-deepest-leaves-sum Medium
1315-sum-of-nodes-with-even-valued-grandparent Medium
1319-number-of-operations-to-make-network-connected Medium
1376-time-needed-to-inform-all-employees Medium
1448-count-good-nodes-in-binary-tree Medium
1457-pseudo-palindromic-paths-in-a-binary-tree Medium
1462-course-schedule-iv Medium
1519-number-of-nodes-in-the-sub-tree-with-the-same-label Medium
1559-detect-cycles-in-2d-grid Medium
1609-even-odd-tree Medium
1765-map-of-highest-peak Medium
1905-count-sub-islands Medium
1926-nearest-exit-from-entrance-in-maze Medium
2101-detonate-the-maximum-bombs Medium
2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph Medium
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph Medium
2385-amount-of-time-for-binary-tree-to-be-infected Medium
2415-reverse-odd-levels-of-binary-tree Medium
2492-minimum-score-of-a-path-between-two-cities Medium
2658-maximum-number-of-fish-in-a-grid Medium
2685-count-the-number-of-complete-components Medium
2812-find-the-safest-path-in-a-grid Medium
3286-find-a-safe-walk-through-a-grid Medium
3619-count-islands-with-total-value-divisible-by-k Medium
3905-multi-source-flood-fill Medium
3910-count-connected-subgraphs-with-even-node-sum Hard

Topological Sort

Problem Name Difficulty
0207-course-schedule Medium
0210-course-schedule-ii Medium
0310-minimum-height-trees Medium
0802-find-eventual-safe-states Medium
0851-loud-and-rich Medium
1462-course-schedule-iv Medium
2192-all-ancestors-of-a-node-in-a-directed-acyclic-graph Medium

String Matching

Problem Name Difficulty
0796-rotate-string Easy
3474-lexicographically-smallest-generated-string Hard

Data Stream

Problem Name Difficulty
0295-find-median-from-data-stream Hard
0901-online-stock-span Medium

Linked List

Problem Name Difficulty
0023-merge-k-sorted-lists Hard
0024-swap-nodes-in-pairs Medium
0082-remove-duplicates-from-sorted-list-ii Medium
0086-partition-list Medium
0092-reverse-linked-list-ii Medium
0114-flatten-binary-tree-to-linked-list Medium
0116-populating-next-right-pointers-in-each-node Medium
0117-populating-next-right-pointers-in-each-node-ii Medium
0143-reorder-list Medium
0328-odd-even-linked-list Medium
1019-next-greater-node-in-linked-list Medium
1367-linked-list-in-binary-tree Medium
1721-swapping-nodes-in-a-linked-list Medium
2095-delete-the-middle-node-of-a-linked-list Medium
2130-maximum-twin-sum-of-a-linked-list Medium
2181-merge-nodes-in-between-zeros Medium
2487-remove-nodes-from-linked-list Medium
2807-insert-greatest-common-divisors-in-linked-list Medium

Bucket Sort

Problem Name Difficulty
0347-top-k-frequent-elements Medium
0451-sort-characters-by-frequency Medium
0692-top-k-frequent-words Medium

Quickselect

Problem Name Difficulty
0215-kth-largest-element-in-an-array Medium
0347-top-k-frequent-elements Medium
0973-k-closest-points-to-origin Medium

Trie

Problem Name Difficulty
0692-top-k-frequent-words Medium

Tree

Problem Name Difficulty
0098-validate-binary-search-tree Medium
0104-maximum-depth-of-binary-tree Easy
0107-binary-tree-level-order-traversal-ii Medium
0113-path-sum-ii Medium
0114-flatten-binary-tree-to-linked-list Medium
0116-populating-next-right-pointers-in-each-node Medium
0117-populating-next-right-pointers-in-each-node-ii Medium
0129-sum-root-to-leaf-numbers Medium
0173-binary-search-tree-iterator Medium
0199-binary-tree-right-side-view Medium
0230-kth-smallest-element-in-a-bst Medium
0236-lowest-common-ancestor-of-a-binary-tree Medium
0437-path-sum-iii Medium
0450-delete-node-in-a-bst Medium
0508-most-frequent-subtree-sum Medium
0513-find-bottom-left-tree-value Medium
0538-convert-bst-to-greater-tree Medium
0606-construct-string-from-binary-tree Medium
0623-add-one-row-to-tree Medium
0652-find-duplicate-subtrees Medium
0654-maximum-binary-tree Medium
0662-maximum-width-of-binary-tree Medium
0690-employee-importance Medium
0863-all-nodes-distance-k-in-binary-tree Medium
0951-flip-equivalent-binary-trees Medium
0958-check-completeness-of-a-binary-tree Medium
0979-distribute-coins-in-binary-tree Medium
0988-smallest-string-starting-from-leaf Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1026-maximum-difference-between-node-and-ancestor Medium
1038-binary-search-tree-to-greater-sum-tree Medium
1110-delete-nodes-and-return-forest Medium
1302-deepest-leaves-sum Medium
1305-all-elements-in-two-binary-search-trees Medium
1315-sum-of-nodes-with-even-valued-grandparent Medium
1325-delete-leaves-with-a-given-value Medium
1367-linked-list-in-binary-tree Medium
1372-longest-zigzag-path-in-a-binary-tree Medium
1376-time-needed-to-inform-all-employees Medium
1448-count-good-nodes-in-binary-tree Medium
1457-pseudo-palindromic-paths-in-a-binary-tree Medium
1519-number-of-nodes-in-the-sub-tree-with-the-same-label Medium
1530-number-of-good-leaf-nodes-pairs Medium
1609-even-odd-tree Medium
2196-create-binary-tree-from-descriptions Medium
2265-count-nodes-equal-to-average-of-subtree Medium
2385-amount-of-time-for-binary-tree-to-be-infected Medium
2415-reverse-odd-levels-of-binary-tree Medium

Binary Search Tree

Problem Name Difficulty
0098-validate-binary-search-tree Medium
0173-binary-search-tree-iterator Medium
0230-kth-smallest-element-in-a-bst Medium
0450-delete-node-in-a-bst Medium
0538-convert-bst-to-greater-tree Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1038-binary-search-tree-to-greater-sum-tree Medium
1305-all-elements-in-two-binary-search-trees Medium

Binary Tree

Problem Name Difficulty
0098-validate-binary-search-tree Medium
0104-maximum-depth-of-binary-tree Easy
0107-binary-tree-level-order-traversal-ii Medium
0113-path-sum-ii Medium
0114-flatten-binary-tree-to-linked-list Medium
0116-populating-next-right-pointers-in-each-node Medium
0117-populating-next-right-pointers-in-each-node-ii Medium
0129-sum-root-to-leaf-numbers Medium
0173-binary-search-tree-iterator Medium
0199-binary-tree-right-side-view Medium
0230-kth-smallest-element-in-a-bst Medium
0236-lowest-common-ancestor-of-a-binary-tree Medium
0437-path-sum-iii Medium
0450-delete-node-in-a-bst Medium
0508-most-frequent-subtree-sum Medium
0513-find-bottom-left-tree-value Medium
0538-convert-bst-to-greater-tree Medium
0606-construct-string-from-binary-tree Medium
0623-add-one-row-to-tree Medium
0652-find-duplicate-subtrees Medium
0654-maximum-binary-tree Medium
0662-maximum-width-of-binary-tree Medium
0863-all-nodes-distance-k-in-binary-tree Medium
0951-flip-equivalent-binary-trees Medium
0958-check-completeness-of-a-binary-tree Medium
0979-distribute-coins-in-binary-tree Medium
0988-smallest-string-starting-from-leaf Medium
1008-construct-binary-search-tree-from-preorder-traversal Medium
1026-maximum-difference-between-node-and-ancestor Medium
1038-binary-search-tree-to-greater-sum-tree Medium
1110-delete-nodes-and-return-forest Medium
1302-deepest-leaves-sum Medium
1305-all-elements-in-two-binary-search-trees Medium
1315-sum-of-nodes-with-even-valued-grandparent Medium
1325-delete-leaves-with-a-given-value Medium
1367-linked-list-in-binary-tree Medium
1372-longest-zigzag-path-in-a-binary-tree Medium
1448-count-good-nodes-in-binary-tree Medium
1457-pseudo-palindromic-paths-in-a-binary-tree Medium
1530-number-of-good-leaf-nodes-pairs Medium
1609-even-odd-tree Medium
2196-create-binary-tree-from-descriptions Medium
2265-count-nodes-equal-to-average-of-subtree Medium
2385-amount-of-time-for-binary-tree-to-be-infected Medium
2415-reverse-odd-levels-of-binary-tree Medium

Iterator

Problem Name Difficulty
0173-binary-search-tree-iterator Medium

Geometry

Problem Name Difficulty
0973-k-closest-points-to-origin Medium
2101-detonate-the-maximum-bombs Medium

Number Theory

Problem Name Difficulty
1627-graph-connectivity-with-threshold Hard
1979-find-greatest-common-divisor-of-array Easy
2807-insert-greatest-common-divisors-in-linked-list Medium
3312-sorted-gcd-pair-queries Hard
3336-find-the-number-of-subsequences-with-equal-gcd Hard
3658-gcd-of-odd-and-even-sums Easy
3867-sum-of-gcd-of-formed-pairs Medium
3896-minimum-operations-to-transform-array-into-alternating-prime Medium

Game Theory

Problem Name Difficulty
0486-predict-the-winner Medium
1406-stone-game-iii Hard
1561-maximum-number-of-coins-you-can-get Medium

Counting Sort

Problem Name Difficulty
1833-maximum-ice-cream-bars Medium
3517-smallest-palindromic-rearrangement-i Medium

Merge Sort

Problem Name Difficulty
0023-merge-k-sorted-lists Hard
3737-count-subarrays-with-majority-element-i Medium

Combinatorics

Problem Name Difficulty
2063-vowels-of-all-substrings Medium
3312-sorted-gcd-pair-queries Hard
3518-smallest-palindromic-rearrangement-ii Hard

Sweep Line

Problem Name Difficulty
0986-interval-list-intersections Medium

Minimax

Problem Name Difficulty
1406-stone-game-iii Hard

Zero-Sum Game

Problem Name Difficulty
1406-stone-game-iii Hard

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