radix_sort.cpp

#include <iostream>
using namespace std;

int getMax(int arr[], int n)
{
    int mx = arr[0];
    for (int i = 1; i < n; i++)
        if (arr[i] > mx)
            mx = arr[i];
    return mx;
}

void countSort(int arr[], int n, int exp)
{
    int output[n];
    int i, count[10] = {0};

    for (i = 0; i < n; i++)
        count[ (arr[i]/exp)%10 ]++;

    for (i = 1; i < 10; i++)
        count[i] += count[i - 1];

    for (i = n - 1; i >= 0; i--)
    {
        output[count[ (arr[i]/exp)%10 ] - 1] = arr[i];
        count[ (arr[i]/exp)%10 ]--;
    }

    for (i = 0; i < n; i++)
        arr[i] = output[i];
}

void radixsort(int arr[], int n)
{
    int m = getMax(arr, n);
    for (int exp = 1; m/exp > 0; exp *= 10)
        countSort(arr, n, exp);
}

int main()
{
    int n;
    cin>>n;
    int* arr=new int[n];
    for(int i=0;i<n;i++){
        cin>>arr[i];
    }
    radixsort(arr, n);
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
    return 0;
}