Compilare: user.cpp: In function ‘void BKT(std::vector<int>, int)’: user.cpp:26:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v.size();i++) ~^~~~~~~~~ user.cpp:27:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<v.size();j++) ~^~~~~~~~~ user.cpp:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<v.size();k++) ~^~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:45:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bigfour.in","r",stdin); ^ user.cpp:46:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bigfour.out","w",stdout); ^