<p>You are given an integer array <code>arr</code>.</p>

<p>We split <code>arr</code> into some number of <strong>chunks</strong> (i.e., partitions), and individually sort each chunk. After concatenating them, the result should equal the sorted array.</p>

<p>Return <em>the largest number of chunks we can make to sort the array</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> arr = [5,4,3,2,1]
<strong>Output:</strong> 1
<strong>Explanation:</strong>
Splitting into two or more chunks will not return the required result.
For example, splitting into [5, 4], [3, 2, 1] will result in [4, 5, 1, 2, 3], which isn&#39;t sorted.
</pre>

<p><strong class="example">Example 2:</strong></p>

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

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= arr.length &lt;= 2000</code></li>
	<li><code>0 &lt;= arr[i] &lt;= 10<sup>8</sup></code></li>
</ul>

#include <vector>
#include <algorithm>

using namespace std;

class Solution {
public:
    int maxChunksToSorted(vector<int>& arr) {
        int n = arr.size();
        vector<int> maxLeft(n), minRight(n);
        
        maxLeft[0] = arr[0];
        for (int i = 1; i < n; ++i) {
            maxLeft[i] = max(maxLeft[i - 1], arr[i]);
        }
        
        minRight[n - 1] = arr[n - 1];
        for (int i = n - 2; i >= 0; --i) {
            minRight[i] = min(minRight[i + 1], arr[i]);
        }
        
        int chunks = 0;
        for (int i = 0; i < n - 1; ++i) {
            if (maxLeft[i] <= minRight[i + 1]) {
                ++chunks;
            }
        }
        
        return chunks + 1;
    }
};

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