LightOj 1023 Discovering Permutations Solution

Problem Link :https://lightoj.com/problem/discovering-permutations 

Solution in C++:

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

#include <bits/stdc++.h>

using namespace std;

int ans=0;

void permute(string a, int l, int r,int k)

{

    if(ans>k)

   return ;

    if ((l == r)&&(ans<=k))

    {

        ans++;

        if(ans<=k)

            cout<<a<<endl;

    }

    else

    {

        for (int i = l; i <= r; i++)

        {

            swap(a[l], a[i]);

            permute(a, l+1, r,k);

        }

    }

}

int main()

{

    long long n,t,i,k,r,ts=1;

    string s="ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    cin>>t;

    while(t--)

    {

        ans=0;

        cin>>n>>k;

        cout<<"Case "<<ts<<":"<<endl;

        ts++;

        string a;

        for(i=0; i<n; i++)

        {

            a+=s[i];

        }

        permute(a,0,n-1,k);

    }

    return 0;

}