<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>

#include<algorithm>
#include<queue>

using namespace std;

class Solution {
public:
    struct node{
        int v, max_v, min_v;
    };

    void push(stack<node>& s1, int v){
        node tmp;
        if (s1.empty()){
            tmp.v = v;
            tmp.max_v = v;
            tmp.min_v = v;
        }
        else{
            tmp.v = v;
            tmp.max_v = max(v, s1.top().max_v);
            tmp.min_v = min(v, s1.top().min_v);
        }
        s1.push(tmp);
    }

    void pop(stack<node>& s1, stack<node>& s2){
        if (!s2.empty()){
            s2.pop();
        }
        else{
            while (!s1.empty()){
                push(s2, s1.top().v);
                s1.pop();
            }
            s2.pop();
        }
    }

    int longestSubarray(vector<int>& nums, int limit) {
        int n = nums.size();
        stack<node> s1, s2;
        int ans = 0;
        for (int i=0; i<n; i++){
            int diff;
            diff = max( abs(nums[i] - max(s1.empty()?nums[i]:s1.top().max_v, s2.empty()?nums[i]:s2.top().max_v)), abs(nums[i]-min(s1.empty()?nums[i]:s1.top().min_v, s2.empty()?nums[i]:s2.top().min_v)));
            while (diff > limit){
                pop(s1, s2);
                diff = max( abs(nums[i] - max(s1.empty()?nums[i]:s1.top().max_v, s2.empty()?nums[i]:s2.top().max_v)), abs(nums[i]-min(s1.empty()?nums[i]:s1.top().min_v, s2.empty()?nums[i]:s2.top().min_v)));
            }

            push(s1, nums[i]);
            if (s1.size() + s2.size() > ans){
                ans = s1.size() + s2.size();
            }
            cout << s1.size() + s2.size() << endl;
        }
        return ans;
    }
};
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