[환미니니] Week6 문제풀이

container-with-most-water/hwanmini.js

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+// 시간복잡도: O(n)
+// 공간복잡도: O(1)
+
+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+var maxArea = function(height) {
+    let maxArea = 0;
+
+    let leftIdx = 0;
+    let rightIdx = height.length - 1;
+
+    while (leftIdx <= rightIdx) {
+        const minHeight = Math.min(height[leftIdx], height[rightIdx]);
+        const distance = rightIdx - leftIdx
+
+        maxArea = Math.max(maxArea, distance * minHeight);
+
+        if (height[leftIdx] < height[rightIdx]) leftIdx++
+        else rightIdx--
+    }
+
+    return maxArea
+};
+
+console.log(maxArea([1,8,6,2,5,4,8,3,7])) //49
+console.log(maxArea([1,1])) //1

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

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+// 시간복잡도
+// addWord: O(n) (n은 추가하는 단어의 길이)
+// search: O(m^n) (m은 각 노드의 최대 자식 수, n은 검색하는 단어의 길이)
+
+// 공간복잡도
+// addWord: O(n) (n은 추가하는 단어의 길이)
+// search: O(n) (n은 검색하는 단어의 길이, 재귀 호출 스택의 깊이)
+
+class TrieNode {
+    constructor() {
+        this.children = {}
+        this.endOfWord = false
+    }
+}
+
+class WordDictionary {
+    constructor() {
+        this.root = new TrieNode()
+    }
+    addWord(word) {
+        let curNode = this.root
+
+        for (let i = 0 ; i < word.length; i++) {
+            if (!curNode.children[word[i]]) {
+                curNode.children[word[i]] = new TrieNode();
+            }
+
+            curNode = curNode.children[word[i]];
+        }
+
+        curNode.endOfWord = true
+    }
+    search(word) {
+        return this.searchInNode(word, this.root);
+    }
+
+    searchInNode(word, node) {
+        let curNode = node;
+
+        for (let i = 0; i < word.length; i++) {
+            if (word[i] === '.') {
+                for (let key in curNode.children) {
+                    if (this.searchInNode(word.slice(i + 1), curNode.children[key])) return true
+                }
+                return false
+            }
+
+            if (word[i] !== '.') {
+                if (!curNode.children[word[i]]) return false
+                curNode = curNode.children[word[i]];
+            }
+        }
+
+        return curNode.endOfWord
+    }
+}
+
+
+const wordDictionary = new WordDictionary();
+wordDictionary.addWord("bad");
+wordDictionary.addWord("dad");
+wordDictionary.addWord("mad");
+console.log(wordDictionary.search("pad")); // return False
+console.log(wordDictionary.search("bad")); // return True
+console.log(wordDictionary.search(".ad")); // return True
+console.log(wordDictionary.search("b..")); // return True
+
+

spiral-matrix/hwanmini.js

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+// 시간복잡도 O(n * m)
+// 공간복잡도 O(n * m)
+
+const isVisited = (matrix, row, col) => {
+    return matrix[row][col] === '#'
+}
+
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function(matrix) {
+    const result = []
+
+    const colLen = matrix[0].length;
+    const rowLen = matrix.length
+
+    let direction = 'right'
+    let row = 0;
+    let col = 0;
+    while (result.length < colLen * rowLen ) {
+        result.push(matrix[row][col])
+        matrix[row][col] = '#'
+
+        if (direction === 'right') {
+            if (isVisited(matrix, row, col+1) || col === colLen - 1) {
+                direction = 'down'
+                row++
+            } else {
+                col++
+            }
+        } else if (direction === 'down') {
+            if ((row + 1 < rowLen &&  isVisited(matrix, row+1, col) || row === rowLen - 1)) {
+                direction = 'left'
+                col--
+            } else {
+                row++
+            }
+        } else if (direction === 'left') {
+            if ((col > 0 && isVisited(matrix, row, col-1) || col === 0)) {
+                direction = 'up'
+                row--
+            } else {
+                col--
+            }
+        } else if (direction === 'up') {
+            if ( (row > 0 && isVisited(matrix,row-1, col))) {
+                direction = 'right'
+                col++
+            } else {
+                row--
+            }
+        }
+
+    }
+
+    return result
+};
+
+
+
+console.log(spiralOrder([
+    [1,2,3],
+    [4,5,6],
+    [7,8,9]])) // [1,2,3,6,9,8,7,4,5]
+

valid-parentheses/hwanmini.js

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+// 시간복잡도: O(n)
+// 공간복잡도: O(n)
+
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isValid = function(s) {
+    if (s.length % 2 !== 0) return false
+
+   const stack = []
+
+    const opener = {
+        "(" : ")",
+        "{": "}",
+        "[": "]"
+    }
+
+    for (let i = 0 ; i < s.length; i++) {
+        if (s[i] in opener) {
+            stack.push(s[i]);
+        } else {
+            if (opener[stack.at(-1)] === s[i]) {
+                stack.pop()
+            } else {
+                return false
+            }
+        }
+    }
+
+
+    return stack.length === 0
+};
+
+console.log(isValid("()")); // true
+console.log(isValid("()[]{}")); // true
+console.log(isValid("(]")); // false
+console.log(isValid("([])")); // true
+console.log(isValid("([}}])")); // true