Compilare: main.cpp: In function 'bool compare(const std::pair<int, int>&, const std::pair<int, int>&)': main.cpp:15:13: warning: statement has no effect [-Wunused-value] 15 | a.first < b.first; | ~~~~~~~~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for(int i = 0; i < a.size(); ++i){ | ~~^~~~~~~~~~ main.cpp: In function 'bool compare(const std::pair<int, int>&, const std::pair<int, int>&)': main.cpp:16:1: warning: control reaches end of non-void function [-Wreturn-type] 16 | } | ^