Compilare: user.cpp: In function ‘void Merge(std::pair<int, int>, std::pair<int, int>)’: user.cpp:29:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < l[x.first][x.second].size(); i++){ ^ user.cpp: In function ‘void solve()’: user.cpp:65:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < s[i].size(); j++) ^ user.cpp:66:61: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int p = 0; p < l[s[i][j].first][s[i][j].second].size(); p++){ ^ user.cpp:90:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(nr == s[0].size()) ^ user.cpp: In function ‘int main()’: user.cpp:96:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.in", "r", stdin); ^ user.cpp:97:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.out", "w", stdout); ^ user.cpp:98:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:100:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ user.cpp:103:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^