208. Implement Trie (Prefix Tree)

Author: gwbaik9717

implement-trie-prefix-tree/gwbaik9717.js

@@ -0,0 +1,70 @@
+var Node = function () {
+  this.children = new Map();
+  this.isEnd = false;
+};
+
+var Trie = function () {
+  this.head = new Node();
+};
+
+/**
+ * @param {string} word
+ * @return {void}
+ */
+Trie.prototype.insert = function (word) {
+  let current = this.head;
+
+  for (const chr of word) {
+    if (!current.children.has(chr)) {
+      current.children.set(chr, new Node());
+    }
+
+    current = current.children.get(chr);
+  }
+
+  current.isEnd = true;
+};
+
+/**
+ * @param {string} word
+ * @return {boolean}
+ */
+Trie.prototype.search = function (word) {
+  let current = this.head;
+
+  for (const chr of word) {
+    if (!current.children.has(chr)) {
+      return false;
+    }
+
+    current = current.children.get(chr);
+  }
+
+  return current.isEnd;
+};
+
+/**
+ * @param {string} prefix
+ * @return {boolean}
+ */
+Trie.prototype.startsWith = function (prefix) {
+  let current = this.head;
+
+  for (const chr of prefix) {
+    if (!current.children.has(chr)) {
+      return false;
+    }
+
+    current = current.children.get(chr);
+  }
+
+  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)
+ */