Compilare: main.cpp: In function 'int nr_valid(std::vector<int>)': main.cpp:26:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | for(int i=v.size()/2;i<v.size()-1;i++) | ~^~~~~~~~~~~ main.cpp:33:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | for(int i=0;i<v.size()/2;i++) | ~^~~~~~~~~~~ main.cpp:45:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 45 | for(int i=v.size()/2-1;i<v.size()-2;i++) | ~^~~~~~~~~~~