Compilare: user.cpp: In function ‘void Back()’: user.cpp:58:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( j = 0 ; j < G[st[i]].size() ; j ++ ) ^ user.cpp: In function ‘void Read()’: user.cpp:21:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d%d" , &n , &K , &d ); ^ user.cpp:24:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &nr ); ^ user.cpp:26:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &x) , G[i].pb(x); ^ user.cpp: In function ‘int main()’: user.cpp:82:26: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(in,"r",stdin); ^ user.cpp:83:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(out,"w",stdout); ^