Compilare: main.cpp: In function 'int pairup(int)': main.cpp:14:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<v[i].size(); j++) ~^~~~~~~~~~~~ main.cpp: In function 'void dfs(int)': main.cpp:30:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();j++) ~^~~~~~~~~~~~