Compilare: main.cpp:3:0: warning: ignoring #pragma gcc optimize [-Wunknown-pragmas] #pragma gcc optimize("O3") main.cpp: In function 'int main()': main.cpp:48:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("inversmodular.in","r",stdin); ^ main.cpp:49:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("inversmodular.out","w",stdout); ^