[hsskey] Week 06 Solutions

container-with-most-water/hsskey.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+var maxArea = function(height) {
+    let result = 0
+    let l = 0;
+    let r = height.length - 1;
+
+    while(l < r) {
+        const area = (r - l) * Math.min(height[l], height[r]);
+        result = Math.max(result, area);
+
+        if(height[l] < height[r]) {
+            l += 1;
+        } else {
+            r -= 1;
+        }
+    }
+    return result
+};

design-add-and-search-words-data-structure/hsskey.js

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+class TrieNode {
+    constructor() {
+        this.children = {};
+        this.word = false;
+    }
+}
+
+class WordDictionary {
+    constructor() {
+        this.root = new TrieNode();
+    }
+
+    addWord(word) {
+        let cur = this.root;
+        for (let c of word) {
+            if (!cur.children[c]) {
+                cur.children[c] = new TrieNode();
+            }
+            cur = cur.children[c];
+        }
+        cur.word = true;
+    }
+
+    search(word) {
+        const dfs = (j, root) => {
+            let cur = root;
+            for (let i = j; i < word.length; i++) {
+                const c = word[i];
+                if (c === '.') {
+                    for (let child of Object.values(cur.children)) {
+                        if (dfs(i + 1, child)) {
+                            return true;
+                        }
+                    }
+                    return false;
+                } else {
+                    if (!cur.children[c]) {
+                        return false;
+                    }
+                    cur = cur.children[c];
+                }
+            }
+            return cur.word;
+        };
+        return dfs(0, this.root);
+    }
+}

longest-increasing-subsequence/hsskey.js

@@ -0,0 +1,16 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var lengthOfLIS = function(nums) {
+    const lis = new Array(nums.length).fill(1);
+
+    for(let i = nums.length - 2; i >= 0; i--) {
+        for(let j = i + 1; j < nums.length; j++) {
+            if(nums[i] < nums[j]) {
+                lis[i] = Math.max(lis[i], 1 + lis[j])
+            }
+        }
+    }
+    return Math.max(...lis)
+};

spiral-matrix/hsskey.js

@@ -0,0 +1,41 @@
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function(matrix) {
+    if (matrix.length === 0) return [];
+
+    const res = [];
+    let left = 0, right = matrix[0].length;
+    let top = 0, bottom = matrix.length;
+
+    while (left < right && top < bottom) {
+        // 상단 행 왼쪽 → 오른쪽
+        for (let i = left; i < right; i++) {
+            res.push(matrix[top][i]);
+        }
+        top += 1;
+
+        // 오른쪽 열 위 → 아래
+        for (let i = top; i < bottom; i++) {
+            res.push(matrix[i][right - 1]);
+        }
+        right -= 1;
+
+        if (!(left < right && top < bottom)) break;
+
+        // 하단 행 오른쪽 → 왼쪽
+        for (let i = right - 1; i >= left; i--) {
+            res.push(matrix[bottom - 1][i]);
+        }
+        bottom -= 1;
+
+        // 왼쪽 열 아래 → 위
+        for (let i = bottom - 1; i >= top; i--) {
+            res.push(matrix[i][left]);
+        }
+        left += 1;
+    }
+
+    return res;
+};

valid-parentheses/hsskey.js

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+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isValid = function(s) {
+    const stack = []
+
+    const pair = {
+        ')' : '(',
+        '}' : '{',
+        ']' : '['
+    }
+
+    for (let item of s) {
+        // 여는 괄호
+        if(item === '(' || item === '{' || item === '[') {
+            stack.push(item)
+        // stack길이가 0 or 닫는 괄호 케이스
+        } else if (stack.length === 0 || stack.pop() !== pair[item]) {
+            return false
+        }
+    }
+
+    return stack.length === 0
+};