solve: implement trie prefix tree

Author: tolluset

implement-trie-prefix-tree/tolluset.ts

@@ -0,0 +1,97 @@
+class TrieNode {
+  public children: Map<string, TrieNode>;
+  public isEnd: boolean;
+
+  constructor() {
+    this.children = new Map();
+    this.isEnd = false;
+  }
+}
+
+class Trie {
+  private root: TrieNode;
+
+  constructor() {
+    this.root = new TrieNode();
+  }
+
+  /**
+   * TC: O(n)
+   * SC: O(n)
+   * */
+  insert(word: string): void {
+    let node = this.root;
+
+    for (const char of word) {
+      if (!node.children.has(char)) {
+        node.children.set(char, new TrieNode());
+      }
+
+      node = node.children.get(char)!;
+    }
+
+    node.isEnd = true;
+  }
+
+  /**
+   * TC: O(n)
+   * SC: O(n)
+   * */
+  search(word: string): boolean {
+    let node = this.root;
+
+    for (const char of word) {
+      if (!node.children.has(char)) {
+        return false;
+      }
+
+      node = node.children.get(char)!;
+    }
+
+    return node.isEnd;
+  }
+
+  /**
+   * TC: O(n)
+   * SC: O(n)
+   * */
+  startsWith(prefix: string): boolean {
+    let node = this.root;
+
+    for (const char of prefix) {
+      if (!node.children.has(char)) {
+        return false;
+      }
+
+      node = node.children.get(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)
+ */
+
+const trie = new Trie();
+
+trie.insert("apple");
+
+const tc1 = trie.search("apple"); // return True
+console.info("🚀 : tolluset.ts:59: tc1=", tc1);
+
+const tc2 = trie.search("app"); // return False
+console.info("🚀 : tolluset.ts:61: tc2=", tc2);
+
+const tc3 = trie.startsWith("app"); // return True
+console.info("🚀 : tolluset.ts:63: tc3=", tc3);
+
+trie.insert("app");
+
+const tc4 = trie.search("app"); // return True
+console.info("🚀 : tolluset.ts:66: tc4=", tc4);