Compilare: user.cpp: In function ‘void buildfail()’: user.cpp:44:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < q.size() ; ++ i) { ^ user.cpp: In function ‘void revbfs()’: user.cpp:76:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < node->matches.size() ; ++ j) { ^ user.cpp: In function ‘int main()’: user.cpp:83:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.in", "r", stdin); ^ user.cpp:84:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.out", "w", stdout); ^