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Trie - tree based data structure #104
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20 changes: 20 additions & 0 deletions
src/_DataStructures_/Trees/Trie/Node.js
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| class TrieNode { | ||
| constructor(char) { | ||
| this.char = char; | ||
| this.children = []; | ||
| this.isEndOfWord = false; | ||
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| // mark all the alphabets as null | ||
| for (let i = 0; i < 26; i += 1) this.children[i] = null; | ||
| } | ||
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| markAsLeaf() { | ||
| this.isEndOfWord = true; | ||
| } | ||
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| unmarkAsLeaf() { | ||
| this.isEndOfWord = false; | ||
| } | ||
| } | ||
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| module.exports = TrieNode; |
73 changes: 73 additions & 0 deletions
src/_DataStructures_/Trees/Trie/index.js
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,73 @@ | ||
| const Node = require('./Node'); | ||
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| class Trie { | ||
| constructor() { | ||
| this.root = new Node(''); | ||
| } | ||
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| // helper to get the index of a character | ||
| // eslint-disable-next-line class-methods-use-this | ||
| getIndexOfChar(char) { | ||
| return char.charCodeAt(0) - 'a'.charCodeAt(0); | ||
| } | ||
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| insert(key) { | ||
| if (!key) { | ||
| return false; | ||
| } | ||
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| // convert to lower case | ||
| // keys are basically words | ||
| const word = key.toLowerCase(); | ||
| let currentNode = this.root; | ||
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| for (let level = 0; level < word.length; level += 1) { | ||
| const index = this.getIndexOfChar(word[level]); | ||
| if (!currentNode.children[index]) { | ||
| currentNode.children[index] = new Node(word[level]); | ||
| } | ||
| currentNode = currentNode.children[index]; | ||
| } | ||
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| // when we are done with inserting all the character of the word, | ||
| // mark the node as end leaf | ||
| currentNode.markAsLeaf(); | ||
| return true; | ||
| } | ||
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| search(key) { | ||
| if (!key) { | ||
| return false; | ||
| } | ||
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| // convert word to lower case | ||
| const word = key.toLowerCase(); | ||
| let currentNode = this.root; | ||
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| for (let level = 0; level < word.length; level += 1) { | ||
| const index = this.getIndexOfChar(word[level]); | ||
| if (!currentNode.children[index]) { | ||
| return false; | ||
| } | ||
| currentNode = currentNode.children[index]; | ||
| } | ||
| if (currentNode !== null && currentNode.isEndOfWord) { | ||
| return true; | ||
| } | ||
| return false; | ||
| } | ||
| } | ||
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| // const words = ['bed', 'ball', 'apple', 'java', 'javascript']; | ||
| // const trie = new Trie(); | ||
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| // words.forEach(word => trie.insert(word)); | ||
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| // console.log(trie.root); | ||
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| // console.log(trie.search(words[3])); | ||
| // console.log(trie.search('word')); | ||
| // console.log(trie.search(words[4])); | ||
| // console.log(trie.search('random')); | ||
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| module.exports = Trie; |
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