Compilare: user.cpp: In function ‘int solve(int)’: user.cpp:30:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:35:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%lld %lld\n",&k,&q); ^ user.cpp:36:24: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s+1,100002,f); ^ user.cpp:39:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%lld",&n); ^ In file included from /usr/include/stdio.h:936:0, from user.cpp:1: In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘int main()’ at user.cpp:36:24: /usr/include/x86_64-linux-gnu/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); ^