Compilare: main.cpp: In function 'int main()': main.cpp:66:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<Z.size(); i++) ~^~~~~~~~~ main.cpp:43:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("hack.in","w",stdout); ^ main.cpp:53:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("hack.in","r",stdin); ^ main.cpp:60:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("hack.out","w",stdout); ^