| Title | Solution | Time | Space | Difficulty | Note |
|---|---|---|---|---|---|
| Build Array from Permutation | Java Python | O(n) | O(n) | Easy | Array, Implementation |
| Concatenation of Array | Java Python | O(n) | O(n*2) | Easy | Array, Implementation |
| Running Sum of 1d Array | Java Python | O(n) | O(n) | Easy | Array, Prefix Sum |
| Richest Customer Wealth | Java Python | O(n*m) | O(n*m) | Easy | Array, Matrix |
| Shuffle the Array | Java Python | O(n/2) | O(n) | Easy | Array, Implementation |
| Kids With the Greatest Number of Candies | Java Python | O(n) | O(n) | Easy | Array, Implementation |
| Two Sum | Java Python | O(n) | O(n) | Easy | Array, HashTable, HashMap |
| Find N Unique Integers Sum up to Zero | Java Python | O(n/2) | O(n) | Easy | Array, Math |
| Lucky Numbers in a Matrix | Java Python | O(n*m) | O(1) | Easy | Array, Matrix |
| Transpose Matrix | Java Python | O(n*m) | O(n+m) | Easy | Array, Matrix |
| Title | Solution | Time | Space | Difficulty | Note |
|---|---|---|---|---|---|
| Sqrt(x) | Java | O(log(n)) | O(1) | Easy | Math, Binary Search |
| Guess Number Higher or Lower | Java | O(log(n)) | O(1) | Easy | Binary Search, Interactive |
| First Bad Version | Java | O(log(n)) | O(1) | Easy | Binary Search, Interactive |
| Two Sum II - Input array is sorted | Java | O(log(n)) | O(1) | Easy | Array, Two Pointers, Binary Search |
| Valid Perfect Square | Java | O(log(n)) | O(1) | Easy | Math, Binary Search |
| Arranging Coins | Java | O(1) | O(1) | Easy | Math |
| Kth Missing Positive Number | Java | O(n) | O(1) | Easy | Array, Binary Search |
| Peak Index in a Mountain Array | Java | O(log(n)) | O(1) | Easy | Array, Binary Search |
| Count Negative Numbers in a Sorted Matrix | Java | O(n*m) | O(1) | Easy | 2D Array, Matrix, Binary Search |
| Intersection of Two Arrays | Java | O(n) | O(n) | Easy | Array, HashTable, HashSet |
| Intersection of Two Arrays II | Java | O(n) | O(n) | Easy | Array, HashTable, HashMap |
| Title | Solution | Time | Space | Difficulty | Note |
|---|---|---|---|---|---|
| Count Items Matching a Rule | Java | O(1) | O(1) | Easy | Array, String |