Compilare: main.cpp: In function 'void invx(std::vector<std::pair<int, int> >&)': main.cpp:14:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i) ~^~~~~~~~~ main.cpp: In function 'void invy(std::vector<std::pair<int, int> >&)': main.cpp:19:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i) ~^~~~~~~~~ main.cpp: In function 'std::pair<std::pair<int, int>, std::pair<int, int> > patr(std::vector<std::pair<int, int> >&)': main.cpp:25:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i) { ~^~~~~~~~~ main.cpp: In function 'bool verif(std::vector<std::pair<int, int> >&, int)': main.cpp:36:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i) ~^~~~~~~~~ main.cpp: In function 'bool check(int)': main.cpp:58:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<p.size(); ++i) ~^~~~~~~~~