111 lines
2.7 KiB
Markdown
111 lines
2.7 KiB
Markdown
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---
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title: Compare a list of strings
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id: 596e457071c35c882915b3e4
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challengeType: 5
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forumTopicId: 302235
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---
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## Description
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<section id='description'>
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Given a <a href="https://en.wikipedia.org/wiki/List_(abstract_data_type)" title="wp: List_(abstract_data_type)" target="_blank">list</a> of arbitrarily many strings, implement a function for each of the following conditions:
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<ul>
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<li>test if they are all lexically equal</li>
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<li>test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)</li>
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</ul>
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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: <code>allEqual</code> should be a function.
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testString: assert(typeof allEqual === 'function');
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- text: <code>azSorted</code> should be a function.
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testString: assert(typeof azSorted === 'function');
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- text: <code>allEqual(["AA", "AA", "AA", "AA"])</code> should return true.
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testString: assert(allEqual(testCases[0]));
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- text: <code>azSorted(["AA", "AA", "AA", "AA"])</code> should return false.
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testString: assert(!azSorted(testCases[0]));
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- text: <code>allEqual(["AA", "ACB", "BB", "CC"])</code> should return false.
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testString: assert(!allEqual(testCases[1]));
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- text: <code>azSorted(["AA", "ACB", "BB", "CC"])</code> should return true.
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testString: assert(azSorted(testCases[1]));
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- text: <code>allEqual([])</code> should return true.
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testString: assert(allEqual(testCases[2]));
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- text: <code>azSorted([])</code> should return true.
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testString: assert(azSorted(testCases[2]));
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- text: <code>allEqual(["AA"])</code> should return true.
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testString: assert(allEqual(testCases[3]));
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- text: <code>azSorted(["AA"])</code> should return true.
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testString: assert(azSorted(testCases[3]));
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- text: <code>allEqual(["BB", "AA"])</code> should return false.
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testString: assert(!allEqual(testCases[4]));
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- text: <code>azSorted(["BB", "AA"])</code> should return false.
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testString: assert(!azSorted(testCases[4]));
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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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function allEqual(arr) {
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return true;
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}
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function azSorted(arr) {
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return true;
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}
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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const testCases = [['AA', 'AA', 'AA', 'AA'], ['AA', 'ACB', 'BB', 'CC'], [], ['AA'], ['BB', 'AA']];
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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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function allEqual(a) {
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let out = true;
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let i = 0;
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while (++i < a.length) {
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out = out && (a[i - 1] === a[i]);
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} return out;
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}
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function azSorted(a) {
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let out = true;
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let i = 0;
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while (++i < a.length) {
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out = out && (a[i - 1] < a[i]);
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} return out;
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}
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```
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</section>
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