Compilare: user.cpp: In function ‘void solve()’: user.cpp:27:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[i].size();j++) if(!viz[v[i].at(j)]) if(mn>val[i]+val[v[i].at(j)]) ^ user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[b].size();j++) if(!viz[v[b].at(j)]) if(v[b].at(j)!=a) ^ user.cpp:35:17: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] viz[b]=1; ^