StringPermutation

// you can use includes, for example:
#include <algorithm>
#include <string>
#include <iostream>
using namespace std;
#define vii vector<pair<int, int>>
#define pii pair<int, int>
#define g0( a ) get<0>( a )
#define g1( a ) get<1>( a )

void Permutate(string& s, int index) {
    if (index == s.size() - 1) {
        cout << s << endl;
    } else {
        for (int i = index; i < s.size(); i++) {
            swap(s[index], s[i]);
            Permutate(s, index + 1);
            swap(s[i], s[index]);
        }    
    }
}

int main() {
    auto s = string{"abcd"};
    Permutate(0);
    
    return 0;
}