2023 Feb, Silver Problem 2. Cow-libi

Hi, I’m having trouble understanding why the solution to this problem is correct.

In this test case:

3 1
249 0 0
249 0 201
249 0 402
450 0 201

The first cow’s alibi should not prove its innocence, because it has just enough time to move to the 3rd grazing. However, if I do a binary search (just like in the solution), my code tells me the first cow’s alibi does prove its innocence. I also tried this test case on Brian Dean’s code and I got the same result. Is there something I’m getting wrong? Thank you!

A cow can be determined to be innocent if it is impossible for her to have travelled between all of the grazings and her alibi.

The output of the solution code is consistent with this.