Compilare: user.cpp: In function ‘void convex_hull(std::vector<punct>&)’: user.cpp:34:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<v.size();i++) ^ user.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++) ^ user.cpp: In function ‘int check(std::vector<punct>&, ll, ll, ll)’: user.cpp:65:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(logn=1;(1<<logn)<=v.size();logn++);logn--; ^ user.cpp:67:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(x+(1<<i)<v.size()-1 && a*v[x+(1<<i)].x+b*v[x+(1<<i)].y>a*v[x+(1<<i)+1].x+b*v[x+(1<<i)+1].y) x+=1<<i; ^ user.cpp: In function ‘void inc(int&)’: user.cpp:100:33: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(pars,1,buff,stdin); ^ user.cpp: In function ‘int main()’: user.cpp:115:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tri3.in", "r", stdin); ^ user.cpp:116:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tri3.out", "w", stdout); ^