Compilare: user.cpp: In function ‘int solve()’: user.cpp:40:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < dependency[index].size(); i++) { ^ user.cpp:46:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘void readInput()’: user.cpp:14:37: 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:15:39: 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); ^ user.cpp:16:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.cpp:18:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &a, &b); ^