<p>Given an array of integers <code>nums</code>, find the maximum length of a subarray where the product of all its elements is positive.</p>

<p>A subarray of an array is a consecutive sequence of zero or more values taken out of that array.</p>

<p>Return <em>the maximum length of a subarray with positive product</em>.</p>

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

<pre>
<strong>Input:</strong> nums = [1,-2,-3,4]
<strong>Output:</strong> 4
<strong>Explanation:</strong> The array nums already has a positive product of 24.
</pre>

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

<pre>
<strong>Input:</strong> nums = [0,1,-2,-3,-4]
<strong>Output:</strong> 3
<strong>Explanation:</strong> The longest subarray with positive product is [1,-2,-3] which has a product of 6.
Notice that we cannot include 0 in the subarray since that&#39;ll make the product 0 which is not positive.</pre>

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

<pre>
<strong>Input:</strong> nums = [-1,-2,-3,0,1]
<strong>Output:</strong> 2
<strong>Explanation:</strong> The longest subarray with positive product is [-1,-2] or [-2,-3].
</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>-10<sup>9</sup> &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution {
public:
    int getMaxLen(vector<int>& nums) {
        int maxlen = 0;
        for (int neg = false, i = 0, n = size(nums), prev = -1, zprev = -1; i < n; ++i) {
            if (nums[i] == 0) {
                zprev = i;
                prev = -1;
                neg = false;
            }
            else if (nums[i] < 0) {
                neg = !neg;
                if (prev == -1)
                    prev = i;                
            }
            if (neg)
                maxlen = max(maxlen, i - prev);
            else
                maxlen = max(maxlen, i - zprev);
        }
        return maxlen;
    }
};

/*
maxlen = 0
neg = false
if nums[i] == 0
    prev = i
    neg = false
else if nums[i] < 0
    if !neg
        neg = true
        prev = i
maxlen = max(maxlen, i - prev - neg)
*/
60500