Compilare: main.cpp:6:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("O3") main.cpp:7:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("unroll-loops") main.cpp: In member function 'void InputReader::nxt()': main.cpp:18:48: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, sizeof(char), BUFF_SIZE, f); ^