Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:29:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it = 0; it < v[nod].size(); ++it) ^ user.cpp: In function ‘int main()’: user.cpp:100:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size() - 1; ++i) ^ user.cpp:38:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in","r",stdin); ^ user.cpp:39:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out","w",stdout); ^ user.cpp:40:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:43:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^