Кунн строки

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <string>
#include <algorithm>
#include <string>
#include <deque>
#include <queue>
#include <iomanip>
#include <set>
#include <map>

#define F first
#define S second

using namespace std;

const long double eps2 = 0.0000005;
const long double eps1 = 1e-5;
const long double pi = 3.1415926535897932;

vector <int> used, p;
vector <string> str;
map<string, vector<int> > shrt;

bool try_kunn(int v)
{
    if (used[v])
        return false;
    used[v] = 1;
    for (int i = 0; i < (shrt.begin() + v).size(); i++)
    {
        int to = shrt[v][i];
        if (p[to] == -1 || try_kunn(p[to]))
        {
            p[to] = v;
            return true;
        }
    }
    return false;
}

int main()
{
    ios_base::sync_with_stdio(0);
    freopen("input.txt", "r", stdin);
    //      freopen("output.txt", "w", stdout);

    int n;
    cin >> n;
    p.resize(n, -1);
    str.resize(n);
    string s, st;
    int ans = 0;
    for (int t = 0; t < n; t++)
    {
        cin >> str[t];
        int k = str[t].size();
        for (int i = 0; i < k + 3; i++)
            for (int j = i + 1; j < k + 3; j++)
                for (int l = j + 1; l < k + 3; l++)
                    for (int r = l + 1; r < k + 3; r++)
                    {
                        st = "";
                        if (i < k)
                            st = st + s[i];
                        if (j < k)
                            st = st + s[j];
                        if (l < k)
                            st = st + s[l];
                        if (r < k)
                            st = st + s[r];
                        if (shrt[st].size() == 0 || shrt[st].back() != t)
                        {
                            shrt[st].push_back(t);
                            /*ans++;
                            cout << st << endl;*/
                        }

                    }

    }
    bool y;
    int i = 0;
    for (map<string, vector<int> > ::iterator ii = shrt.begin(); ii != shrt.end(); ii++)
    {
        used.assign(shrt.size(), 0);
        y = try_kunn(i);
        i++;
        /*for (int i = 0; i < ii -> S.size(); i++)
            cout << ii->S[i] << " ";
            cout << endl;*/
    }
    return 0;
}