Compilare: user.cpp: In function ‘void compute_pi_delta()’: user.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<q.size();i++) ^ user.cpp: In function ‘std::vector<int> get_freq(char*)’: user.cpp:70:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:78:42: 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:79:44: 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); ^ user.cpp:81:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s%d",sir,&n); ^ user.cpp:86:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n%s",sir1); ^