func_code_string: #include <bits/stdc++.h>   using namespace std;   long long mod = 1000000007;   template <typename T>   void debug(vector<T> x) {     for (auto e : x) {       cout << e <<    ;     }     cout <<   n ;   }   void solve() {     long long n, m, x, y;     cin >> n >> m >> x >> y;     vector<pair<long long, long long>> ans;     stack<pair<long long, long long>> st;     long long mat[n + 1][m + 1];     for (long long i = 1; i <= n; i++)       for (long long j = 1; j <= m; j++) mat[i][j] = 0;     st.push({x, y});     while (!st.empty()) {       pair<long long, long long> cur = st.top();       if (mat[cur.first][cur.second] == 0) {         mat[cur.first][cur.second] = 1;         ans.push_back({cur.first, cur.second});       }       st.pop();       for (long long i = 1; i <= n; i++) {         if (mat[i][cur.second] == 0) {           st.push({i, cur.second});         }       }       for (long long j = 1; j <= m; j++) {         if (mat[cur.first][j] == 0) {           st.push({cur.first, j});         }       }     }     for (auto x : ans) {       cout << x.first <<     << x.second <<   n ;     }   }   signed main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     long long t = 1;     while (t--) {       solve();     }     return 0;   }   