#817 · #769 · Max Chunks To Make Sorted(最多能完成排序的块)

You are given an array arr that is a permutation of 0 .. n-1. Split the array into some number of contiguous chunks and sort each chunk individually. Return the maximum number of chunks that makes the whole array sorted. Constraints: 1 <= arr.length <= 10, arr is a permutation of 0 .. n-1.