So I just found out that my solution which is almost same as this one gets TLE on test case 8 while latter got AC.

I can't figure-out why this happened?

Problem link -> C.Save More Mice

Solution:

It turns out that Arrays.sort() in java uses Quicksort which has worst time complexity of O(n^2) and Collections.sort() uses that has time complexity of O(nlogn).

refer to this article for more information.