Compilare: main.cpp: In function 'void D()': main.cpp:40:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<o.size();++i) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:57:98: 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),freopen("ahocorasick.out","w",stdout),fread(ra,1,M,stdin); ^ main.cpp:57:98: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:57:98: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]