Compilare: main.cpp: In function 'void f1(int, int)': main.cpp:15:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | for(int p1=0,p2=a[i].size()-1; p1<a[i].size(); p2=p1++) | ~~^~~~~~~~~~~~ main.cpp: In function 'void f2(int, int, int)': main.cpp:27:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for(int p=0; p<a[i].size(); p++) | ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:47:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 47 | for(int i=0; i<a.size(); i++) | ~^~~~~~~~~ main.cpp:76:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 76 | for(int i=1; i<a.size(); i++) | ~^~~~~~~~~