Compilare: main.cpp: In function 'int main()': main.cpp:30:23: warning: suggest parentheses around '-' inside '<<' [-Wparentheses] ll ans = (1LL << F-1) * (1LL << F-1); ~^~ main.cpp:30:38: warning: suggest parentheses around '-' inside '<<' [-Wparentheses] ll ans = (1LL << F-1) * (1LL << F-1); ~^~ main.cpp:34:25: warning: suggest parentheses around '-' inside '<<' [-Wparentheses] ans -= (1LL << F-1); ~^~ main.cpp:42:34: warning: suggest parentheses around '-' inside '<<' [-Wparentheses] ans += 1LL << j + F-1-c[i].first; ~~~~~~~^~~~~~~~~~~ main.cpp:22:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fft2d.in", "r", stdin); ^ main.cpp:23:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fft2d.out", "w", stdout); ^