Counting Sort is an sorting algorithm, which sorts the integers( or Objects) given in a specific range.

**Algorithm: Time Complexity O(n)**

- Take two arrays, Count[] and Result[] and given array is input[].
- Count[] will store the counts of each integer in the given array.
- Update the Count[] so that each index will store the sum till previous step. (Count[i]=Count[i] + Count[i-1]). Now updated Count[] array will reflect the actual position of each integer in Result[].
- Now navigate the input array taking one element at a time, Count[input[i]] will tell you the index position of input[i] in Result[]. When you do that, decrease the count in Count[input[i]] by 1. See Example

Counting-Sort

**Code**:

**Output** :

Orginal Array [2, 1, 4, 5, 7, 1, 1, 8, 9, 10, 11, 14, 15, 3, 2, 4]
Sorted Array : [0, 1, 1, 1, 2, 2, 3, 4, 4, 5, 7, 8, 9, 10, 11, 14, 15]

*Related*