implement-trie-prefix-tree solution

Author: lhc0506

implement-trie-prefix-tree/lhc0506.js

@@ -0,0 +1,65 @@
+
+var Trie = function() {
+    this.isEnd = false;
+};
+
+/**
+ * @param {string} word
+ * @return {void}
+ */
+Trie.prototype.insert = function(word) {
+    let currentTrie = this;
+    word.split('').forEach(alphabet => {
+        if (!currentTrie[alphabet]) {
+            currentTrie[alphabet] = new Trie();
+        }
+        currentTrie = currentTrie[alphabet];
+    });
+
+    currentTrie.isEnd = true;
+};
+
+/**
+ * @param {string} word
+ * @return {boolean}
+ */
+Trie.prototype.search = function(word) {
+    let currentTrie = this;
+
+    for (let alphabet of word) {
+        if (!currentTrie[alphabet]) {
+            return false;
+        }
+        currentTrie = currentTrie[alphabet];
+    }
+
+    return currentTrie.isEnd;
+};
+
+/**
+ * @param {string} prefix
+ * @return {boolean}
+ */
+Trie.prototype.startsWith = function(prefix) {
+    let currentTrie = this;
+
+    for (let alphabet of prefix) {
+        if (!currentTrie[alphabet]) {
+            return false;
+        }
+        currentTrie = currentTrie[alphabet];
+    }
+
+    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)
+ */
+
+
+// insert 시간복잡도: O(n), search 시간복잡도: O(n), startsWith 시간복잡도: O(n)