Compilare: user.cpp: In function ‘void solve()’: user.cpp:27:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < G[x].size(); i++) ^ user.cpp:22:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp:22:15: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp:22:18: warning: unused variable ‘val’ [-Wunused-variable] int i, j, k, val, x; ^