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| 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 | + |
| 10 | +class TrieNode { |
| 11 | + private isEnd: boolean = false; |
| 12 | + private freq: number = 0; |
| 13 | + private child: object = {}; |
| 14 | + public constructor() { |
| 15 | + this.isEnd = false; |
| 16 | + this.freq = 0; |
| 17 | + this.child = {}; |
| 18 | + } |
| 19 | +} |
| 20 | + |
| 21 | +class Trie extends TrieNode { |
| 22 | + public root: TrieNode = undefined; |
| 23 | + constructor(trie) { |
| 24 | + super(); |
| 25 | + this.root = new TrieNode(); |
| 26 | + } |
| 27 | + |
| 28 | + /** |
| 29 | + * Inserts a word into the trie. |
| 30 | + * @param {string} word |
| 31 | + * @return {void} |
| 32 | + */ |
| 33 | + 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]; |
| 45 | + } |
| 46 | + |
| 47 | + curNode.isEnd = true; |
| 48 | + curNode.freq += 1; |
| 49 | + } |
| 50 | + |
| 51 | + /** |
| 52 | + * Returns if the word is in the trie. |
| 53 | + * @param {string} word |
| 54 | + * @return {boolean} |
| 55 | + */ |
| 56 | + public search(word: string): boolean {} |
| 57 | + |
| 58 | + /** |
| 59 | + * Returns if there is any word in the trie that starts with the given prefix. |
| 60 | + * @param {string} prefix |
| 61 | + * @return {boolean} |
| 62 | + */ |
| 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 | + } |
| 77 | + } |
| 78 | +} |
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