Compilare: main.cpp: In function 'bool check(int, int&)': main.cpp:11:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 11 | for (int i = 0; i < h[x%MOD].size(); i++) | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:44:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 44 | for (j = 0; j < h[i].size(); j++) | ~~^~~~~~~~~~~~~