Compilare: user.cpp: In function ‘int bfs()’: user.cpp:52:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < v[virf].size() ; ++i){ ^ user.cpp: In function ‘void max_flow()’: user.cpp:69:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < v[2*N + 1].size() ; ++i){ ^ user.cpp: In function ‘void write()’: user.cpp:94:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < sol[i].size() ; ++j) ^