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Commit a81f6e1

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feat(trie): remove method
1 parent 524670e commit a81f6e1

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3 files changed

+137
-0
lines changed

3 files changed

+137
-0
lines changed

‎src/data-structures/trees/trie-1.js

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Original file line numberDiff line numberDiff line change
@@ -67,6 +67,54 @@ class Trie {
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return words;
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}
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/**
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* Return true if found the word to be removed, otherwise false.
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* Iterative approach
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* @param {string} word - The word to remove
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* @returns {boolean}
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*/
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remove(word) {
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const stack = [];
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let curr = this;
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for (const char of word) {
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if (!curr.children[char]) { return false; }
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stack.push(curr);
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curr = curr.children[char];
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}
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if (!curr.isWord) { return false; }
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let node = stack.pop();
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do {
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node.children = {};
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node = stack.pop();
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} while (node && !node.isWord);
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return true;
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}
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/**
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* Return true if found the word to be removed, otherwise false.
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* recursive approach
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* @param {string} word - The word to remove
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* @returns {boolean}
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*/
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remove2(word, i = 0, parent = this) {
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if (i === word.length - 1) {
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return true;
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}
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const child = parent.children[word.charAt(i)];
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if (!child) return false;
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const found = this.remove(word, i + 1, child);
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if (found) {
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delete parent.children[word.charAt(i)];
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}
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return true;
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}
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}
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// Aliases

‎src/data-structures/trees/trie.js

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,40 @@ class Trie {
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curr.isWord = true;
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}
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/**
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* Return true if found the word to be removed, otherwise false.
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* @param {string} word - The word to remove
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* @returns {boolean}
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*/
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remove(word) {
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return this.removeHelper(word);
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}
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/**
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* Remove word from trie, return true if found, otherwise false.
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* @param {string} word - The word to remove.
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* @param {Trie} parent - The parent node.
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* @param {number} index - The index.
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* @param {number} meta.stop - Keeps track of the last letter that won't be removed.
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* @returns {boolean}
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*/
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removeHelper(word, parent = this, index = 0, meta = { stop: 0 }) {
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if (index === word.length) {
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parent.isWord = false;
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if (Object.keys(parent.children)) { meta.stop = index; }
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return true;
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}
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const child = parent.children[word.charAt(index)];
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if (!child) { return false; }
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if (parent.isWord) { meta.stop = index; }
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const found = this.removeHelper(word, child, index + 1, meta);
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// deletes all the nodes beyond `meta.stop`.
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if (found && index >= meta.stop) {
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delete parent.children[word.charAt(index)];
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}
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return found;
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}
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/**
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* Retun last node that matches word or prefix or false if not found.
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* @param {string} word - Word to search.

‎src/data-structures/trees/trie.spec.js

Lines changed: 55 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -69,6 +69,13 @@ describe('Trie', () => {
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expect(trie.startsWith('do')).toEqual(true);
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});
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it('should match full words if partial is set', () => {
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expect(trie.search('dogs', {
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partial: true,
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})).toEqual(true);
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expect(trie.startsWith('dogs')).toEqual(true);
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});
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it('should not match non existing words', () => {
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expect(trie.search('doors')).toEqual(false);
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});
@@ -129,5 +136,53 @@ describe('Trie', () => {
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expect(words).toEqual([]);
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});
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});
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describe('remove', () => {
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it('should remove a word', () => {
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trie = new Trie();
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trie.insert('a');
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expect(trie.remove('a')).toEqual(true);
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expect(trie.getAllWords()).toEqual([]);
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});
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it('should remove word and keep other words', () => {
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trie = new Trie();
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trie.insert('a');
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trie.insert('ab');
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expect(trie.remove('a')).toEqual(true);
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expect(trie.getAllWords()).toEqual(['ab']);
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});
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it('should remove surrounding word', () => {
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trie = new Trie();
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trie.insert('a');
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trie.insert('ab');
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expect(trie.remove('ab')).toEqual(true);
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expect(trie.getAllWords()).toEqual(['a']);
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});
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it('should return false when word is not found', () => {
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expect(trie.remove('not there')).toBe(false);
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});
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it('should remove words in between and still match', () => {
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expect(trie.remove('dog')).toBe(true);
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expect(trie.search('dogs')).toBe(true);
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expect(trie.startsWith('dog')).toBe(true);
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expect(trie.getAllWords()).toEqual([
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'dogs', 'door', 'day', 'cat',
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]);
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});
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it('should remove word and no longer match partials', () => {
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expect(trie.remove('dogs')).toBe(true);
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expect(trie.search('dogs')).toBe(false);
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expect(trie.search('dog')).toBe(true);
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expect(trie.startsWith('dog')).toBe(true);
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expect(trie.getAllWords()).toEqual([
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'dog', 'door', 'day', 'cat',
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]);
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});
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});
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});
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});

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