<p>Given a binary array <code>nums</code>, you should delete one element from it.</p>

<p>Return <em>the size of the longest non-empty subarray containing only </em><code>1</code><em>&#39;s in the resulting array</em>. Return <code>0</code> if there is no such subarray.</p>

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

<pre>
<strong>Input:</strong> nums = [1,1,0,1]
<strong>Output:</strong> 3
<strong>Explanation:</strong> After deleting the number in position 2, [1,1,1] contains 3 numbers with value of 1&#39;s.
</pre>

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

<pre>
<strong>Input:</strong> nums = [0,1,1,1,0,1,1,0,1]
<strong>Output:</strong> 5
<strong>Explanation:</strong> After deleting the number in position 4, [0,1,1,1,1,1,0,1] longest subarray with value of 1&#39;s is [1,1,1,1,1].
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,1,1]
<strong>Output:</strong> 2
<strong>Explanation:</strong> You must delete one element.
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>nums[i]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution {
public:
    int longestSubarray(vector<int>& nums) {

        int prefix_frequency_array[nums.size()];

        int postfix_frequency_array[nums.size()];

        int postfix_frequency = 0;

        int prefix_frequency = 0;

        for (int i=0,j=nums.size()-1;i<nums.size();i++,j--) {

            if (nums[i] == 1) prefix_frequency++;

            if (nums[j] == 1) postfix_frequency++;

            if (nums[i] == 0) {
                prefix_frequency = 0;
            }

            if (nums[j] == 0) {
                postfix_frequency = 0;
            }

            prefix_frequency_array[i] = prefix_frequency;
            postfix_frequency_array[j] = postfix_frequency;
        }

        if (postfix_frequency == nums.size()) return postfix_frequency-1;

        int max_subarry = 0;

        for (int i=0;i<nums.size();i++) {
            int prefix_freq = 0;

            int postfix_freq = 0;

            if (nums[i] == 0) {
                if (i==0) {
                    prefix_freq = 0;
                } else {
                    prefix_freq = prefix_frequency_array[i-1];
                }

                if (i==nums.size()-1) {
                    postfix_freq = 0;
                }
                else {
                    postfix_freq = postfix_frequency_array[i+1];
                }

                if (max_subarry < prefix_freq+postfix_freq+1) {
                    max_subarry = prefix_freq+postfix_freq;
                }
            }

        }

        return max_subarry;
        
    }
};
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