Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < V[nod].size(); i++ ) ~~^~~~~~~~~~~~~~~ user.cpp:18:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if( F[nod] == 0 ) ^ user.cpp: In function ‘int main()’: user.cpp:78:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( Sol.size() == 2 * N ){ ~~~~~~~~~~~^~~~~~~~ user.cpp:79:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < Sol.size(); i++ ) ~~^~~~~~~~~~~~