Compilare: main.cpp: In function 'int pairup(int)': main.cpp:36:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | for(i = 0; i < v[u].size(); i++) | ~~^~~~~~~~~~~~~ main.cpp:46:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 46 | for(i = 0; i < v[u].size(); i++) | ~~^~~~~~~~~~~~~