Permutation UVa 941

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

int main()
{
    string str;
    vector<char>str2;
    int i,j,t,n,ln,tln,fac,div,x,y;
    cin>>t;
    while(t--){
        cin>>str;
        cin>>n;
        ln=str.size();
        tln=ln;
        y=0;
        while(y<ln){
            fac=1;
            for(j=1;j<=tln;j++)
                fac=fac*j;
            div=fac/ln;
            x=n/div;
            str2.push_back(str[x]);
            str.erase(str.begin()+(x+1));
            n=n-div*x;
            y++;
            tln--;
        }
        for(j=0;j<ln;j++)
            cout<<str2[j];
        cout<<endl;
    }
    return 0;
}