Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:13:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[nod].size();i++) { ^ user.cpp: In function ‘int main()’: user.cpp:45:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sol.size()*2==n) { ^ user.cpp:47:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<sol.size();i++) ^ user.cpp:36:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("g2mm.in","r",stdin); ^ user.cpp:37:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("g2mm.out","w",stdout); ^ user.cpp:38:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:40:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^