Given an array arr that is a permutation of [0, 1, ..., arr.length - 1], we split the array into some number of "chunks" (partitions), and individually sort each chunk. After concatenating them, the result equals the sorted array.

What is the most number of chunks we could have made?

Example 1:

Input: arr = [4,3,2,1,0]
Output: 1
Explanation:
Splitting into two or more chunks will not return the required result.
For example, splitting into [4, 3], [2, 1, 0] will result in [3, 4, 0, 1, 2], which isn‘t sorted.

Example 2:

Input: arr = [1,0,2,3,4]
Output: 4
Explanation:
We can split into two chunks, such as [1, 0], [2, 3, 4].
However, splitting into [1, 0], [2], [3], [4] is the highest number of chunks possible.

Note:

• arr will have length in range [1, 10].
• arr[i] will be a permutation of [0, 1, ..., arr.length - 1]
  .

解題思路：

一次循環，每次把循環中最大的數字找出來，如果在到達這個數字之前沒有出現新數組的話，清零並且數量加1，重復操作。

1. class Solution {
2. public:
3. int maxChunksToSorted(vector<int>& arr) {
4. if(arr.size()==0) return 0;
5. int max_partition=0;
6. int count=0;
8. for(int i=0;i<arr.size();i++){
10. if(arr[i]>max_partition) max_partition=arr[i];
11. if(max_partition == i) {count++;max_partition=0;}
13. }
14. return count;
16. }
17. };

769. Max Chunks To Make Sorted