Hi I've been looking at solutions for https://oj.uz/problem/view/NOI19_feast and I saw some kind of binary search but I don't really understand the idea behind it. Can someone help? Thanks

Given an array of n integers, split it into at most k subarray that are pair-wise disjoint so that the sum of those subarray are maximized.

N, K <= 3e5

|Ai| <= 1e9