implement trie prefix tree solution

Author: robinyoon-dev

implement-trie-prefix-tree/robinyoon-dev.js

@@ -0,0 +1,66 @@
+var TrieNode = function () {
+    this.children = {};
+    this.isEnd = false;
+}
+
+var Trie = function () {
+    this.root = new TrieNode();
+};
+
+/** 
+ * @param {string} word
+ * @return {void}
+ */
+Trie.prototype.insert = function (word) {
+    let currentNode = this.root;
+    for (let i = 0; i < word.length; i++) {
+        let char = word[i];
+        if (!currentNode.children[char]) {
+            currentNode.children[char] = new TrieNode();
+
+        }
+        currentNode = currentNode.children[char];
+    }
+
+    currentNode.isEnd = true;
+};
+
+/** 
+ * @param {string} word
+ * @return {boolean}
+ */
+Trie.prototype.search = function (word) {
+    let currentNode = this.root;
+    for (let i = 0; i < word.length; i++) {
+        let char = word[i];
+        if (!currentNode.children[char]) {
+            return false;
+        }
+        currentNode = currentNode.children[char];
+    }
+    return currentNode.isEnd;
+};
+
+/** 
+ * @param {string} prefix
+ * @return {boolean}
+ */
+Trie.prototype.startsWith = function (prefix) {
+    let currentNode = this.root;
+    for (let i = 0; i < prefix.length; i++) {
+        let char = prefix[i];
+        if (!currentNode.children[char]) {
+            return false;
+        }
+        currentNode = currentNode.children[char];
+    }
+    return true;
+};
+
+/** 
+ * Your Trie object will be instantiated and called as such:
+ * var obj = new Trie()
+ * obj.insert(word)
+ * var param_2 = obj.search(word)
+ * var param_3 = obj.startsWith(prefix)
+ */