<p>Given an array of integers <code>nums</code> and an integer <code>limit</code>, return the size of the longest <strong>non-empty</strong> subarray such that the absolute difference between any two elements of this subarray is less than or equal to <code>limit</code><em>.</em></p>

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

<pre>
<strong>Input:</strong> nums = [8,2,4,7], limit = 4
<strong>Output:</strong> 2 
<strong>Explanation:</strong> All subarrays are: 
[8] with maximum absolute diff |8-8| = 0 &lt;= 4.
[8,2] with maximum absolute diff |8-2| = 6 &gt; 4. 
[8,2,4] with maximum absolute diff |8-2| = 6 &gt; 4.
[8,2,4,7] with maximum absolute diff |8-2| = 6 &gt; 4.
[2] with maximum absolute diff |2-2| = 0 &lt;= 4.
[2,4] with maximum absolute diff |2-4| = 2 &lt;= 4.
[2,4,7] with maximum absolute diff |2-7| = 5 &gt; 4.
[4] with maximum absolute diff |4-4| = 0 &lt;= 4.
[4,7] with maximum absolute diff |4-7| = 3 &lt;= 4.
[7] with maximum absolute diff |7-7| = 0 &lt;= 4. 
Therefore, the size of the longest subarray is 2.
</pre>

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

<pre>
<strong>Input:</strong> nums = [10,1,2,4,7,2], limit = 5
<strong>Output:</strong> 4 
<strong>Explanation:</strong> The subarray [2,4,7,2] is the longest since the maximum absolute diff is |2-7| = 5 &lt;= 5.
</pre>

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

<pre>
<strong>Input:</strong> nums = [4,2,2,2,4,4,2,2], limit = 0
<strong>Output:</strong> 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>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
	<li><code>0 &lt;= limit &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution {
public:
  /*
  */
  // heaps
  int longestSubarray(vector<int>& nums, int limit) {
    auto maxCmp = [&nums](int lhs, int rhs){ return nums[lhs] < nums[rhs]; };
    auto minCmp = [&nums](int lhs, int rhs){ return nums[lhs] > nums[rhs]; };
    std::priority_queue<int, std::vector<int>, decltype(maxCmp)> maxHeap{maxCmp};
    std::priority_queue<int, std::vector<int>, decltype(minCmp)> minHeap{minCmp};
    int maxLength{};
    int left{};
    for(int right = 0; right < nums.size(); ++right) {
      maxHeap.push(right);
      minHeap.push(right);
      if(nums[maxHeap.top()] - nums[minHeap.top()] > limit) {
        left = std::min(maxHeap.top(), minHeap.top()) + 1;
      }
      while(!maxHeap.empty() && maxHeap.top() < left) {
        maxHeap.pop();
      }
      while(!minHeap.empty() && minHeap.top() < left) {
        minHeap.pop();
      }
      maxLength = std::max(maxLength, right - left + 1);
    }
    return maxLength;
  }

  /*
  // multiset
  int longestSubarray(vector<int>& nums, int limit) {
    auto cmp = [&nums](int lhs, int rhs){ return nums[lhs] < nums[rhs]; };
    std::multiset<int, decltype(cmp)> window{cmp};
    int maxLength{};
    int left{};
    for(int right = 0; right < nums.size(); ++right) {
      window.insert(right);
      if(nums[*window.rbegin()] - nums[*window.begin()] > limit) {
        left = std::min(*window.rbegin(), *window.begin()) + 1;
      }
      std::erase_if(window, [left](int i){ return i < left; });
      maxLength = std::max(maxLength, right - left + 1);
    }
    return maxLength;
  }
  */
};
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