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implemented counting sort

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Lines changed: 28 additions & 0 deletions

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	`1`	`+const countingSort = (arr, min, max) => {`
	`2`	`+ // No need to sort the array if the array only has one element or empty`
	`3`	`+ if (arr.length < 2) return arr;`
	`4`	`+`
	`5`	`+ // Auxiliary array`
	`6`	`+ const counts = [];`
	`7`	`+`
	`8`	`+ for (let i = min; i <= max; i += 1) {`
	`9`	`+ counts[i] = 0;`
	`10`	`+ }`
	`11`	`+`
	`12`	`+ // increase index value`
	`13`	`+ arr.forEach((el) => { counts[el] += 1; });`
	`14`	`+`
	`15`	`+ const result = [];`
	`16`	`+`
	`17`	`+ // put everything in a new array`
	`18`	`+ for (let i = min; i <= max; i += 1) {`
	`19`	`+ while (counts[i] > 0) {`
	`20`	`+ result.push(i);`
	`21`	`+ counts[i] -= 1;`
	`22`	`+ }`
	`23`	`+ }`
	`24`	`+`
	`25`	`+ return result;`
	`26`	`+};`
	`27`	`+`
	`28`	`+module.exports = countingSort;`

Lines changed: 21 additions & 0 deletions

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	`1`	`+const countingSort = require('../../src/sorting/counting');`
	`2`	`+`
	`3`	`+describe('counting sort unit test:', () => {`
	`4`	`+ it('Test#1 simple', async () => {`
	`5`	`+ const want = [2, 3, 5, 6, 7, 9];`
	`6`	`+ const got = countingSort([5, 3, 7, 6, 2, 9], 2, 9);`
	`7`	`+ expect(got).toEqual(want);`
	`8`	`+ });`
	`9`	`+`
	`10`	`+ it('Test#2 duplicate value', async () => {`
	`11`	`+ const want = [2, 3, 5, 5, 6, 7, 7, 9];`
	`12`	`+ const got = countingSort([5, 3, 7, 6, 2, 9, 7, 5], 2, 9);`
	`13`	`+ expect(got).toEqual(want);`
	`14`	`+ });`
	`15`	`+`
	`16`	`+ it('Test#3 with negative value', async () => {`
	`17`	`+ const want = [-7, -7, -3, 6, 17, 34, 42, 50, 52, 83, 87, 89, 96];`
	`18`	`+ const got = countingSort([83, 52, 89, 42, 6, 87, 50, 17, 34, 96, -7, -3, -7], -7, 96);`
	`19`	`+ expect(got).toEqual(want);`
	`20`	`+ });`
	`21`	`+});`

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