Compilare: main.cpp: In function 'int main()': main.cpp:40:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G.size();j++) ~^~~~~~~~~ main.cpp:41:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k=0;k<G[j].size();k++) ~^~~~~~~~~~~~ main.cpp:50:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j<G.size(); j++) ~^~~~~~~~~ main.cpp:51:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k<G[j].size(); k++) ~^~~~~~~~~~~~