diff --git a/Sorts/CountingSort.js b/Sorts/CountingSort.js index 2003cfb73..a31ea4455 100644 --- a/Sorts/CountingSort.js +++ b/Sorts/CountingSort.js @@ -8,31 +8,31 @@ * 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 +const countingSort = (arr, min, max) => { + // Create an auxiliary resultant array + const res = [] + // Create and initialize the frequency[count] array + const count = new Array(max - min + 1).fill(0) + // Populate the freq array + for (let i = 0; i < arr.length; i++) { + count[arr[i] - min]++ } - - for (i = 0; i < arr.length; i++) { - count[arr[i]]++ + // Create a prefix sum array out of the frequency[count] array + count[0] -= 1 + for (let i = 1; i < count.length; i++) { + count[i] += count[i - 1] } - - for (i = min; i <= max; i++) { - while (count[i]-- > 0) { - arr[z++] = i - } + // Populate the result array using the prefix sum array + for (let i = arr.length - 1; i >= 0; i--) { + res[count[arr[i] - min]] = arr[i] + count[arr[i] - min]-- } - - return arr + return res } /** -* Implementation of Counting Sort -*/ + * Implementation of Counting Sort + */ const array = [3, 0, 2, 5, 4, 1] // Before Sort console.log('\n- Before Sort | Implementation of Counting Sort -')