Compilare: main.cpp: In function 'int main()': main.cpp:20:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for (k=0; k<x[m].size (); k++) | ~^~~~~~~~~~~~~ main.cpp:34:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | for (k=0; k<x[m].size (); k++) | ~^~~~~~~~~~~~~