Compilare: user.cpp: In function ‘bool verf1(int, int)’: user.cpp:23:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(G[i].size()<N-1){ ^ user.cpp:47:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G[x].size();++j) ^ user.cpp:49:27: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(x!=i && !verf(i,G[x][j])) ^ user.cpp:63:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(G[i].size()<N-1){ ^