countSort.cpp

#include <iostream>
#include <vector>
using namespace std;
//time O(n+k) n is elemnts in array and k is the range of elements
//space O(n+k) array of size(n+k) has to be created
void counting_sort(int a[], int n)
{
	//Largest Element
	int largest = -1;
	for (int i = 0; i < n; i++)
	{
		largest = max(largest, a[i]);
	}
	//create a count array/vector
	vector<int> freq(largest + 1, 0);
	//Update the freq array
	for (int i = 0; i < n; i++)
	{
		freq[a[i]]++;
	}
	//Put back the elements from freq into original array
	int j = 0;
	for (int i = 0; i <= largest; i++)
	{
		while (freq[i] > 0)
		{
			a[j] = i;
			freq[i]--;
			j++;
		}
	}
	return;
}
int main()
{
	int arr[] = {88, 97, 10, 12, 15, 1, 5, 6, 12, 5, 8};
	int n = sizeof(arr) / sizeof(int);
	counting_sort(arr, n);
	for (int i = 0; i < n; i++)
	{
		cout << arr[i] << " ";
	}
	return 0;
}