Compilare: main.cpp: In function 'll char_hash(char)': main.cpp:24:19: warning: array subscript has type 'char' [-Wchar-subscripts] ret[ch] = (ret[ch - 1] * basis)%mod; ^ main.cpp:27:17: warning: array subscript has type 'char' [-Wchar-subscripts] return ret[x]; ^ main.cpp: In function 'void solve_len(int, std::vector<int>&)': main.cpp:51:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = len; i < buf.size(); ++i){ ~~^~~~~~~~~~~~ main.cpp:49:8: warning: variable 'prev' set but not used [-Wunused-but-set-variable] ll prev = curr; ^~~~ main.cpp: In function 'void do_test()': main.cpp:86:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i =0 ; i < pats.size(); ++i) ~~^~~~~~~~~~~~~ main.cpp:92:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < pats.size(); ++i){ ~~^~~~~~~~~~~~~