Compilare: user.cpp: In function ‘long long int check(int, int, int)’: user.cpp:64:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] long long c = first_0_in_suffix[r + 1] == pos0.size() ? 0 : sum_of_0_positions(pos0[first_0_in_suffix[r + 1]],pos0[first_0_in_suffix[r + 1] + taken_pos(pos + 1,r) - 1]); ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:72:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d\n",&n,&q); ^ user.cpp:73:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s + 1,NMAX + 5,f); ^ user.cpp:100:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&l,&r); ^ In file included from /usr/include/stdio.h:936:0, from /usr/include/c++/6/cstdio:42, from user.cpp:3: In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘int main()’ at user.cpp:73:25: /usr/include/bits/stdio2.h:261:58: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^