Today i tried to solve IOI 2015 horses problem. I observed that maximum profit can be gained by selling all horses on the same year. Obvious bruteforce would be to check every year.

Here is my solution:

int init(int n,int* x,int* y){
  ll MAX = 0;
  ll h = 1;
  for(int i=1;i<=n;i++){
    h *= x[i];
    MAX = max(MAX,h*y[i]);
  }
  return MAX;
}

But we have to keep the maximum profit. It is given that the answer could be very large therefore output it modulo 1e9+7; Because of the constraints above code works for subtask 1.

For remaining subtasks it won't. For keeping MAX i thought of maintaining a pair in the form of {n/ 1e9+7 , n% 1e9+7}. I think it could work.

But What if h exceeds integer bounds. we can't keep it modulo 1e9+7 because then h*y[i] will be wrong. How do i keep h such that it won't exceed integer bounds AND it won't give a wrong answer for h*y[i].

Thank you for your time