design-add-and-search-words-data-structure solution

Author: lhc0506

design-add-and-search-words-data-structure/lhc0506.js

@@ -0,0 +1,67 @@
+const Node = function() {
+    this.children = {};
+    this.isEnd = false;
+}
+
+var WordDictionary = function() {
+    this.root = new Node();
+};
+
+/**
+ * @param {string} word
+ * @return {void}
+ */
+WordDictionary.prototype.addWord = function(word) {
+    let currentNode = this.root;
+
+    for (let char of word) {
+        if (!currentNode.children[char]) {
+            currentNode.children[char] = new Node();
+        }
+        currentNode = currentNode.children[char];
+    }
+
+    currentNode.isEnd = true;
+};
+
+/**
+ * @param {string} word
+ * @return {boolean}
+ */
+WordDictionary.prototype.search = function(word) {
+    if (word === undefined) return false;
+    return this._search(this.root, word, 0);
+};
+
+WordDictionary.prototype._search = function(node, word, index) {
+    if (index === word.length) {
+        return node.isEnd;
+    }
+
+    const char = word[index];
+
+    if (char !== '.') {
+        const child = node.children[char];
+        return child ? this._search(child, word, index + 1) : false;
+    }
+
+    for (const key in node.children) {
+        if (this._search(node.children[key], word, index + 1)) {
+            return true;
+        }
+    }
+
+    return false;
+};
+
+/**
+ * Your WordDictionary object will be instantiated and called as such:
+ * var obj = new WordDictionary()
+ * obj.addWord(word)
+ * var param_2 = obj.search(word)
+ */
+
+// n: 단어수, m: 단어 길이
+// addWord: 시간 복잡도 O(m)
+// search: 	시간 복잡도 O(m)
+// 공간 복잡도 O(n * m)