diff --git a/container-with-most-water/hoyeongkwak.ts b/container-with-most-water/hoyeongkwak.ts
new file mode 100644
index 000000000..d45b05019
--- /dev/null
+++ b/container-with-most-water/hoyeongkwak.ts
@@ -0,0 +1,15 @@
+function maxArea(height: number[]): number {
+    let res = 0
+    let l = 0
+    let r = height.length - 1
+    while (l < r) {
+        const area = (r - l) * Math.min(height[l], height[r])
+        res = Math.max(res, area)
+        if (height[l] > height[r]) {
+            r -= 1
+        } else {
+            l += 1
+        }
+    }
+    return res
+};
diff --git a/design-add-and-search-words-data-structure/hoyeongkwak.ts b/design-add-and-search-words-data-structure/hoyeongkwak.ts
new file mode 100644
index 000000000..6578f7c80
--- /dev/null
+++ b/design-add-and-search-words-data-structure/hoyeongkwak.ts
@@ -0,0 +1,63 @@
+/*
+O(n)
+O(n)
+*/
+
+class TriedNode {
+    children: Map<string, TriedNode>
+    isEndOfWord: boolean
+
+    constructor(){
+        this.children = new Map()
+        this.isEndOfWord = false
+    }
+}
+
+class WordDictionary {
+    root: TriedNode
+    constructor() {
+        this.root = new TriedNode()
+    }
+
+    addWord(word: string): void {
+        let node = this.root
+        for (const char of word) {
+            if (!node.children.has(char)) {
+                node.children.set(char, new TriedNode())
+            }
+            node = node.children.get(char)
+        }
+        node.isEndOfWord = true
+    }
+
+    search(word: string): boolean {
+        const searchInNode = (word: string, index: number, node: TriedNode): boolean => {
+            if (index === word.length) return node.isEndOfWord
+
+            const char = word[index]
+
+            if (char === '.') {
+                for (const [, childNode] of node.children) {
+                    if (searchInNode(word, index + 1, childNode)) {
+                        return true
+                    }
+                }
+                return false
+            } else {
+                if (!node.children.has(char)) {
+                    return false
+                }
+                return searchInNode(word, index + 1, node.children.get(char))
+            }
+        }
+        return searchInNode(word, 0, this.root)
+    }
+}
+
+/**
+ * Your WordDictionary object will be instantiated and called as such:
+ * var obj = new WordDictionary()
+ * obj.addWord(word)
+ * var param_2 = obj.search(word)
+ */
+
diff --git a/longest-increasing-subsequence/hoyeongkwak.ts b/longest-increasing-subsequence/hoyeongkwak.ts
new file mode 100644
index 000000000..c01b65929
--- /dev/null
+++ b/longest-increasing-subsequence/hoyeongkwak.ts
@@ -0,0 +1,17 @@
+function lengthOfLIS(nums: number[]): number {
+    let res = 1
+    const dp: number[] = Array.from(nums).fill(1)
+    for (let i = nums.length - 2; i >= 0; i--) {
+        let curr = 1
+        let j = i
+        while(j < nums.length && curr < res + 1) {
+            if (nums[j] > nums[i]) {
+                curr = Math.max(curr, 1 + dp[j])
+            }
+            j++
+        }
+        dp[i] = curr
+        res = Math.max(dp[i], res)
+    }
+    return res
+};
diff --git a/spiral-matrix/hoyeongkwak.ts b/spiral-matrix/hoyeongkwak.ts
new file mode 100644
index 000000000..a963bd8c9
--- /dev/null
+++ b/spiral-matrix/hoyeongkwak.ts
@@ -0,0 +1,34 @@
+function spiralOrder(matrix: number[][]): number[] {
+    const m = matrix.length
+    const n = matrix[0].length
+    const size = m * n
+    let traversed = 0
+    let top = 0
+    let bottom = m - 1
+    let left = 0
+    let right = n - 1
+    const output = []
+
+    while (traversed < size) {
+        for (let i = left; traversed < size && i <= right; i++, traversed++) {
+            output.push(matrix[top][i])
+        }
+        top++
+
+        for (let i = top; traversed < size && i <= bottom; i++, traversed++) {
+            output.push(matrix[i][right])
+        }
+        right--
+                
+        for (let i = right; traversed < size && i >= left; i--, traversed++) {
+            output.push(matrix[bottom][i])
+        }
+        bottom--
+
+        for (let i = bottom; traversed < size && i >= top; i--, traversed++) {
+            output.push(matrix[i][left])
+        }
+        left++
+    }
+    return output
+};
diff --git a/valid-parentheses/hoyeongkwak.ts b/valid-parentheses/hoyeongkwak.ts
new file mode 100644
index 000000000..f255ccc0c
--- /dev/null
+++ b/valid-parentheses/hoyeongkwak.ts
@@ -0,0 +1,18 @@
+function isValid(s: string): boolean {
+    const stack: string[] = []
+    const strMap = new Map<string, string>([
+        ['(', ')'],
+        ['[', ']'] ,
+        ['{', '}']
+    ])
+    for (let str of s) {
+        if (strMap.has(str)) {
+            stack.push(strMap.get(str))
+        } else if (stack.length > 0 && stack[stack.length - 1] === str) {
+            stack.pop()
+        } else {
+            return false
+        }
+    }
+    return stack.length === 0
+};