Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < G[X].size(); i ++ ) { ^ user.cpp: In function ‘int main(int, const char**)’: user.cpp:125:24: warning: ‘col’ may be used uninitialized in this function [-Wmaybe-uninitialized] out << col << " " << val << endl; ^