Compilare: main.cpp: In function 'void rebuild()': main.cpp:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=mid+1;i<active.size();i++) ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:115:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("peru.in","r",stdin); ^ main.cpp:116:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("peru.out","w",stdout); ^