Compilare: user.cpp: In function ‘void solve()’: user.cpp:49:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < G[nod].size(); ++i ) ^ user.cpp: In function ‘void citire()’: user.cpp:26:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in" , "r" , stdin ); ^ user.cpp:27:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &N , &M ); ^ user.cpp:30:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &x , &y ); ^ user.cpp: In function ‘void solve()’: user.cpp:40:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out" , "w" , stdout ); ^