diff --git a/HamSungJun/Solution_1441.ts b/HamSungJun/Solution_1441.ts
new file mode 100644
index 0000000..024cd25
--- /dev/null
+++ b/HamSungJun/Solution_1441.ts
@@ -0,0 +1,16 @@
+function buildArray (target: number[], n: number): string[] {
+  let cursor = 0
+  const out = []
+  for (let i = 1; i <= n; i++) {
+    if (target[cursor] === i) {
+      out.push('Push')
+      cursor += 1
+      if (cursor === target.length) {
+        break
+      }
+    } else {
+      out.push('Push', 'Pop')
+    }
+  }
+  return out
+};
diff --git a/HamSungJun/Solution_496.ts b/HamSungJun/Solution_496.ts
new file mode 100644
index 0000000..ad46891
--- /dev/null
+++ b/HamSungJun/Solution_496.ts
@@ -0,0 +1,16 @@
+function nextGreaterElement (nums1: number[], nums2: number[]): number[] {
+  const numToIndexMap: Map<number, number> = new Map()
+  for (let i = 0; i < nums2.length; i++) {
+    numToIndexMap.set(nums2[i], i)
+  }
+  return nums1.map(n => {
+    for (let i = numToIndexMap.get(n) as number + 1; i < nums2.length; i++) {
+      if (nums2[i] > n) {
+        return nums2[i]
+      }
+    }
+    return -1
+  })
+};
+
+console.log(nextGreaterElement([4, 1, 2], [1, 3, 4, 2]))
diff --git a/HamSungJun/Solution_821.ts b/HamSungJun/Solution_821.ts
new file mode 100644
index 0000000..6f90694
--- /dev/null
+++ b/HamSungJun/Solution_821.ts
@@ -0,0 +1,40 @@
+function shortestToChar (s: string, c: string): number[] {
+  const charToIndexSet: Set<number> = new Set()
+  const remains = []
+  for (let i = 0; i < s.length; i++) {
+    if (s[i] === c) {
+      charToIndexSet.add(i)
+      remains.push({
+        v: 0,
+        isC: true
+      })
+    } else {
+      remains.push({
+        v: i,
+        isC: false
+      })
+    }
+  }
+  return remains.map(({ v, isC }) => {
+    if (!isC) {
+      return getShortest(v, charToIndexSet)
+    }
+    return 0
+  })
+};
+
+const getShortest = (n: number, indexSet: Set<number>): number => {
+  let left = n - 1
+  let right = n + 1
+  while (true) {
+    if (indexSet.has(left)) {
+      return n - left
+    } else if (indexSet.has(right)) {
+      return right - n
+    }
+    left -= 1
+    right += 1
+  }
+}
+
+console.log(shortestToChar('loveleetcode', 'e'))