Compilare: user.cpp: In function ‘int main()’: user.cpp:54:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (G[it].size() == 0 && dp[it] == (fr.size() - 1)) { ^ user.cpp:20:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.in", "r", stdin); ^ user.cpp:21:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.out", "w", stdout); ^