JavaScript/Sorts/CountingSort.js

/**
 * Counting sort is an algorithm for sorting a collection 
 * of objects according to keys that are small integers.
 * 
 * It is an integer sorting algorithm.
 * 
 * Wikipedia: https://en.wikipedia.org/wiki/Counting_sort
 * Animated Visual: https://www.cs.usfca.edu/~galles/visualization/CountingSort.html
 */

function countingSort (arr, min, max) {
  let i
  let z = 0
  const count = []

  for (i = min; i <= max; i++) {
    count[i] = 0
  }

  for (i = 0; i < arr.length; i++) {
    count[arr[i]]++
  }

  for (i = min; i <= max; i++) {
    while (count[i]-- > 0) {
      arr[z++] = i
    }
  }

  return arr
}

const arr = [3, 0, 2, 5, 4, 1]

// Array before Sort
console.log('-----before sorting-----')
console.log(arr)
// Array after sort
console.log('-----after sorting-----')
console.log(countingSort(arr, 0, 5))