UET Password Generator

//Trần Việt Anh - 14/3/2019 - 5:40PM
#include<iostream>
#include<vector>

using namespace std;

vector<string> result(0, "");

void go(string current, string charset)
{
    if (current.length() < charset.length())
        for (int i = 0; i < charset.length(); i++)
        {
            result.push_back(current + charset[i]);
            go(current + charset[i], charset);
        }
}

int main()
{
    string _set; cin >> _set;
    string s = "";

    //Generate the result
    go(s, _set);

    //Reorder the result to match the output rule
    for (int i = 0; i < result.size() - 1; i++)
        for (int j = i + 1; j < result.size(); j++)
            if (result[i].length() > result[j].length())
            {
                string mid = result[i]; result[i] = result[j]; result[j] = mid;
            }
            else if (result[i].length() == result[j].length() && result[i] > result[j])
            {
                string mid = result[i]; result[i] = result[j]; result[j] = mid;
            }

    //Print the result
    for (int i = 0; i < result.size(); i++)
        cout << result[i] << endl;
}