Compilare: user.cpp: In function ‘void do_magic()’: user.cpp:86:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<v.size();++i) { ^ user.cpp:87:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<w[i].size();++j) { ^ user.cpp: In function ‘int main()’: user.cpp:95:40: 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:96:42: 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:97:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s%d",s,&N); ^ user.cpp:100:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",t); ^