237 lines
5.9 KiB
Markdown
237 lines
5.9 KiB
Markdown
---
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id: 587d8254367417b2b2512c6f
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title: Perform a Subset Check on Two Sets of Data
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challengeType: 1
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forumTopicId: 301707
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---
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## Description
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<section id='description'>
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In this exercise, we are going to perform a subset test on 2 sets of data. We will create a method on our <code>Set</code> data structure called <code>isSubsetOf</code>. This will compare the first set against the second, and if the first set is fully contained within the second, it will return <code>true</code>.
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For example, if <code>setA = ['a','b']</code> and <code>setB = ['a','b','c','d']</code>, then <code>setA</code> is a subset of <code>setB</code>, so <code>setA.isSubsetOf(setB)</code> should return <code>true</code>.
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: Your <code>Set</code> class should have a <code>isSubsetOf</code> method.
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testString: assert((function(){var test = new Set(); return (typeof test.isSubsetOf === 'function')})());
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- text: The first Set() should be contained in the second Set
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testString: assert((function(){var setA = new Set(); var setB = new Set(); setA.add('a'); setB.add('b'); setB.add('c'); setB.add('a'); setB.add('d'); var aIsSubsetOfB = setA.isSubsetOf(setB);return (aIsSubsetOfB === true)})());
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- text: <code>['a', 'b'].isSubsetOf(['a', 'b', 'c', 'd'])</code> should return <code>true</code>
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testString: assert((function(){var setA = new Set(); var setB = new Set(); setA.add('a'); setA.add('b'); setB.add('a'); setB.add('b'); setB.add('c'); setB.add('d'); var aIsSubsetOfB = setA.isSubsetOf(setB); return (aIsSubsetOfB === true)})());
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- text: <code>['a', 'b', 'c'].isSubsetOf(['a', 'b'])</code> should return <code>false</code>
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testString: assert((function(){var setA = new Set(); var setB = new Set(); setA.add('a'); setA.add('b'); setA.add('c'); setB.add('a'); setB.add('b'); var aIsSubsetOfB = setA.isSubsetOf(setB); return (aIsSubsetOfB === false)})());
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- text: <code>[].isSubsetOf([])</code> should return <code>true</code>
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testString: assert((function(){var setA = new Set(); var setB = new Set(); var aIsSubsetOfB = setA.isSubsetOf(setB); return (aIsSubsetOfB === true)})());
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- text: <code>['a', 'b'].isSubsetOf(['c', 'd'])</code> should return <code>false</code>
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testString: assert((function(){var setA = new Set(); var setB = new Set(); setA.add('a'); setA.add('b'); setB.add('c'); setB.add('d'); var aIsSubsetOfB = setA.isSubsetOf(setB); return (aIsSubsetOfB === false)})());
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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class Set {
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constructor() {
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// This will hold the set
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this.dictionary = {};
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this.length = 0;
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}
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// This method will check for the presence of an element and return true or false
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has(element) {
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return this.dictionary[element] !== undefined;
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}
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// This method will return all the values in the set
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values() {
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return Object.keys(this.dictionary);
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}
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// This method will add an element to the set
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add(element) {
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if (!this.has(element)) {
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this.dictionary[element] = true;
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this.length++;
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return true;
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}
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return false;
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}
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// This method will remove an element from a set
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remove(element) {
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if (this.has(element)) {
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delete this.dictionary[element];
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this.length--;
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return true;
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}
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return false;
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}
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// This method will return the size of the set
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size() {
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return this.length;
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}
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// This is our union method
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union(set) {
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const newSet = new Set();
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this.values().forEach(value => {
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newSet.add(value);
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})
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set.values().forEach(value => {
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newSet.add(value);
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})
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return newSet;
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}
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// This is our intersection method
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intersection(set) {
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const newSet = new Set();
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let largeSet;
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let smallSet;
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if (this.dictionary.length > set.length) {
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largeSet = this;
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smallSet = set;
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} else {
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largeSet = set;
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smallSet = this;
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}
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smallSet.values().forEach(value => {
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if (largeSet.dictionary[value]) {
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newSet.add(value);
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}
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})
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return newSet;
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}
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difference(set) {
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const newSet = new Set();
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this.values().forEach(value => {
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if (!set.dictionary[value]) {
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newSet.add(value);
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}
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})
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return newSet;
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}
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// Only change code below this line
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// Only change code above this line
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}
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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class Set {
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constructor() {
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this.dictionary = {};
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this.length = 0;
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}
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has(element) {
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return this.dictionary[element] !== undefined;
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}
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values() {
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return Object.keys(this.dictionary);
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}
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add(element) {
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if (!this.has(element)) {
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this.dictionary[element] = true;
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this.length++;
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return true;
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}
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return false;
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}
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remove(element) {
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if (this.has(element)) {
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delete this.dictionary[element];
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this.length--;
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return true;
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}
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return false;
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}
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size() {
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return this.length;
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}
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union(set) {
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const newSet = new Set();
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this.values().forEach(value => {
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newSet.add(value);
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})
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set.values().forEach(value => {
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newSet.add(value);
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})
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return newSet;
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}
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intersection(set) {
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const newSet = new Set();
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let largeSet;
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let smallSet;
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if (this.dictionary.length > set.length) {
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largeSet = this;
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smallSet = set;
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} else {
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largeSet = set;
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smallSet = this;
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}
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smallSet.values().forEach(value => {
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if (largeSet.dictionary[value]) {
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newSet.add(value);
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}
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})
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return newSet;
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}
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difference(set) {
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const newSet = new Set();
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this.values().forEach(value => {
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if (!set.dictionary[value]) {
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newSet.add(value);
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}
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})
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return newSet;
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}
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isSubsetOf(set) {
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for(const value of this.values()){
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if(!set.dictionary[value]) return false;
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}
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return true
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}
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}
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```
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</section>
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