Compilare: user.cpp: In function ‘long long unsigned int solve_fast(long long unsigned int)’: user.cpp:200:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (dif > max_dif) ^ user.cpp: In function ‘int main()’: user.cpp:218:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gap.in", "r", stdin); ^ user.cpp:219:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gap.out", "w", stdout); ^ user.cpp:221:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:225:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%llu", &x); ^