In the speedbreaker question, why do we need to do: c++ mn[i]=min(mn[i],mn[i-1]),mx[i]=max(mx[i],mx[i-1]);

I (mostly) get everything besides that. Thanks in advance!

Full submission by Zqr123456 on Div 2 contest:

Also, I get why the first condition is necessary for there to be a solutions and I get why the second part of the code finds that good interval, but I'm having a little trouble piecing together the sufficiency of the two to guarantee the right answer. Perhaps this is also why I font understand why you have to do the operations on the mins and maxes too.

#include <iostream>
using namespace std;

int main () {
   cout << "Hello world!\n";
   return 0;
}