Counting Sort Algorithm In Javascript | letsbug

     Hey in this article we implementing counting sort algorithm. If you are new to Data Structures and Algorithms you might have not heard about it. Because this is not taught in the colleges like they teach other algorithms like the bubble sort.

    If you want to see implement more sorting algorithms click here

    So we are going to implement this algorithm in javascript. And if you want to go deep into counting sort and how it works from the basic. You can find many tutorials on the web available. But in this article we are just focused on implementing it javascript. so

Counting Sort In Javascript.

code:

    //counting sort algorithm
    function countingSort(arr: number[]):number[] {
        let max = Math.max(...arr);
        let output: number[] = [];
        let count: number[] = [];
        for (let i = 0; i <= max; i++) {
            count.push(0);
        }
        for (let i = 0; i < arr.length; i++) {
            if(arr[i] > max) continue
            count[arr[i]]++;
        }
        for (let i = 1; i <= max; i++) {
            count[i] += count[i - 1];
        }
        for (let i = arr.length - 1; i >= 0; i--) {
            if(arr[i] > max) continue
            output[count[arr[i]] - 1] = arr[i];
            count[arr[i]]--;
        }
        return output;
    }
    let arr1 = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
    console.log(`Before sorting: ${arr1}
    After sorting: ${countingSort(arr1)}`);

output:

$ node countingSort.js

Before sorting: 10,9,8,7,6,5,4,3,2,1

After sorting: 1,2,3,4,5,6,7,8,9,10

output