New Algorithm: Parity Outlier (#1314)

* [feat] New algorithm

* [test] Add new test for ParityOutlier.js

* [fix] Reset indentation

* [fix] Reset indentation

* [fix] Style changes

* fix: improve code efficiency and a glitch

* test: adds a new possible test case

* fix: style fix

* fix: delete redundant comments and else statements

* [fix] style fix
This commit is contained in:
Arnold Zhou
2023-05-01 16:16:48 +10:00
committed by GitHub
parent 84b01aeb61
commit e6df6ebad6
2 changed files with 63 additions and 0 deletions

33
Maths/ParityOutlier.js Normal file
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/**
* @author mrmagic2020
* @description The function will find the parity outlier from an array of integers.
* @see https://en.wikipedia.org/wiki/Parity_(mathematics)
* @param {number[]} integers - An array of integers.
* @returns {number} - The parity outlier.
* @example parityOutlier([1, 3, 5, 8, 9]) = 8
*/
const parityOutlier = (integers) => {
let oddsCount = 0 // define counter for odd number(s)
let evensCount = 0 // define counter for even number(s)
let odd, even
for (const e of integers) {
if (!Number.isInteger(e)) { // detect non-integer elements
return null
}
if (e % 2 === 0) { // an even number
even = e
evensCount++
} else { // an odd number
odd = e
oddsCount++
}
}
if (oddsCount === 0 || evensCount === 0) return null // array has only odd/even number(s)
if (oddsCount > 1 && evensCount > 1) return null // array has more than one even and odd number
return oddsCount === 1 ? odd : even
}
export { parityOutlier }

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import { parityOutlier } from '../ParityOutlier'
describe('Testing parityOutlier function', () => {
it('should return the odd number in an array of even numbers', () => {
expect(parityOutlier([1, 2, 16, -8848, 5126])).toBe(1)
})
it('should return the even number in an array of odd numbers', () => {
expect(parityOutlier([177, 5, 76, 1919])).toBe(76)
})
it('should, if the given array has only one integer element, return the integer itself', () => {
expect(parityOutlier([83])).toBe(83)
expect(parityOutlier([54])).toBe(54)
})
it('should, if the given array has only an odd and an even number, return the odd outlier', () => {
expect(parityOutlier([1, 2])).toBe(1)
expect(parityOutlier([4, 3])).toBe(3)
})
it('should return null if the given array is empty, contains only one integer, contains non-interger elements or does not have a parity outlier', () => {
expect(parityOutlier([])).toBe(null)
expect(parityOutlier([2])).toBe(null)
expect(parityOutlier([2, {}, 5, 'GitHub'])).toBe(null)
expect(parityOutlier([1, 3, 5, 7, 9])).toBe(null)
expect(parityOutlier([0, 2, 4, 6, 8])).toBe(null)
expect(parityOutlier([1, 3, 5, 7, 2, 4, 6, 8])).toBe(null)
})
})