Compilare: user.cpp: In function ‘void solve()’: user.cpp:55:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[s.x].size();++j) if(!viz[v[s.x][j]]) father = v[s.x][j]; ^ user.cpp:63:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[father].size();++i) if(viz[ v[father][i] ]) u.c += D[ v[father][i] ]; ^