Counting Sort.cpp

//{ Driver Code Starts
//Initial Template for C++

#include <bits/stdc++.h>
using namespace std;
#define RANGE 255


// } Driver Code Ends
//User function Template for C++

class Solution{
    public:
    //Function to arrange all letters of a string in lexicographical 
    //order using Counting Sort.
    string countSort(string arr){
        // code here
        vector<int>freq(26,0);
        for(int i=0;i<arr.length();i++){
            freq[arr[i]-'a']++;
        }
        string ans="";
        for(int i=0;i<26;i++){
            for(int j=0;j<freq[i];j++){
                ans+=i+'a';
            }
        }
        return ans;
    }
};


//{ Driver Code Starts.

int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        string arr;
        cin>>arr;
        Solution obj;
        cout<<obj.countSort(arr)<<endl;
    }
    return 0;
}

// } Driver Code Ends