1- // Trie trie = new Trie();
2- 3- // trie.insert("apple");
4- // trie.search("apple"); // returns true
5- // trie.search("app"); // returns false
6- // trie.startsWith("app"); // returns true
7- // trie.insert("app");
8- // trie.search("app"); // returns true
9- 101class TrieNode {
11- private isEnd : boolean = false ;
12- private freq : number = 0 ;
13- private child : object = { } ;
2+ public root : object = { } ;
143 public constructor ( ) {
15- this . isEnd = false ;
16- this . freq = 0 ;
17- this . child = { } ;
4+ this . root ;
185 }
196}
207
218class Trie extends TrieNode {
22- public root : TrieNode = undefined ;
23- constructor ( trie ) {
9+ public root = undefined ;
10+ public constructor ( ) {
2411 super ( ) ;
25- this . root = new TrieNode ( ) ;
12+ this . root = new TrieNode ( ) . root ;
2613 }
2714
2815 /**
@@ -31,48 +18,47 @@ class Trie extends TrieNode {
3118 * @return {void }
3219 */
3320 public insert ( word : string ) : void {
34- if ( word . length ) return ;
35- let letter : TrieNode = new TrieNode ( ) ;
36- let curNode : TrieNode = new TrieNode ( ) ;
37- let i : number = 0 ;
38- 39- while ( i < word . length ) {
40- letter = word [ i ] ;
41- if ( ! curNode . child . hadOwnProperty ( letter ) ) {
42- curNode . child [ letter ] = new TrieNode ( ) ;
43- }
44- curNode = curNode . child [ letter ] ;
21+ let node = this . root ;
22+ for ( let i = 0 ; i < word . length ; i ++ ) {
23+ node = node [ word [ i ] ] = node [ word [ i ] ] || { } ;
24+ if ( i === word . length - 1 ) node . isTerminal = true ;
4525 }
46- 47- curNode . isEnd = true ;
48- curNode . freq += 1 ;
4926 }
5027
5128 /**
5229 * Returns if the word is in the trie.
5330 * @param {string } word
5431 * @return {boolean }
5532 */
56- public search ( word : string ) : boolean { }
33+ public search ( word : string , isPrefix ?: boolean ) : boolean {
34+ let node = this . root ;
35+ for ( let c of word ) {
36+ if ( ! node [ c ] ) return false ;
37+ node = node [ c ] ;
38+ }
39+ return isPrefix || ! ! node . isTerminal ;
40+ }
5741
5842 /**
5943 * Returns if there is any word in the trie that starts with the given prefix.
6044 * @param {string } prefix
6145 * @return {boolean }
6246 */
63- public startsWith ( prefix ) { }
64- 65- public prefix ( word ) {
66- let letter : TrieNode = new TrieNode ( ) ;
67- let curNode : TrieNode = new TrieNode ( ) ;
68- let i : number = 0 ;
69- 70- while ( i < word . length ) {
71- letter = word [ i ] ;
72- if ( ! curNode . child . hasOwnProperty ( letter ) ) {
73- return null ;
74- curNode = curNode . child [ letter ] ;
75- }
76- }
47+ public startsWith ( prefix : string ) : boolean {
48+ return this . search ( prefix , true ) ;
7749 }
7850}
51+ 52+ const trie = new Trie ( ) ;
53+ 54+ trie . insert ( 'apple' ) ;
55+ const a = trie . search ( 'apple' ) ; // returns true
56+ const b = trie . search ( 'app' ) ; // returns false
57+ const c = trie . startsWith ( 'app' ) ; // returns true
58+ trie . insert ( 'app' ) ;
59+ const d = trie . search ( 'app' ) ; // returns true
60+ 61+ console . log ( 'a' , a ) ;
62+ console . log ( 'b' , b ) ;
63+ console . log ( 'c' , c ) ;
64+ console . log ( 'd' , d ) ;
0 commit comments