<p>You are given a 2D array of integers <code>envelopes</code> where <code>envelopes[i] = [w<sub>i</sub>, h<sub>i</sub>]</code> represents the width and the height of an envelope.</p>

<p>One envelope can fit into another if and only if both the width and height of one envelope are greater than the other envelope&#39;s width and height.</p>

<p>Return <em>the maximum number of envelopes you can Russian doll (i.e., put one inside the other)</em>.</p>

<p><strong>Note:</strong> You cannot rotate an envelope.</p>

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

<pre>
<strong>Input:</strong> envelopes = [[5,4],[6,4],[6,7],[2,3]]
<strong>Output:</strong> 3
<strong>Explanation:</strong> The maximum number of envelopes you can Russian doll is <code>3</code> ([2,3] =&gt; [5,4] =&gt; [6,7]).
</pre>

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

<pre>
<strong>Input:</strong> envelopes = [[1,1],[1,1],[1,1]]
<strong>Output:</strong> 1
</pre>

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

<ul>
	<li><code>1 &lt;= envelopes.length &lt;= 10<sup>5</sup></code></li>
	<li><code>envelopes[i].length == 2</code></li>
	<li><code>1 &lt;= w<sub>i</sub>, h<sub>i</sub> &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:

int lis(vector<int> value,int l, int r, int val){
    while(l<r){
        int m = l+(r-l)/2;
        if(value[m]>=val) r=m;
        else l = m+1;
    }
    return r;
}
static bool comp (vector<int>&a, vector<int>& b){
    if(a[0]==b[0]){
        return a[1]>b[1];
    }
    return a[0]<b[0];
}
    int maxEnvelopes(vector<vector<int>>& envelopes) {
        sort(envelopes.begin(), envelopes.end(), comp);
      
        vector<int> sol;
        int n = envelopes.size();

          for(int i=0;i<n;i++){
            cout<<envelopes[i][1]<<" ";
        }
        sol.push_back(envelopes[0][1]);
        for(int i=1;i<n;i++){
            if(sol[sol.size()-1]<envelopes[i][1]){
                sol.push_back(envelopes[i][1]);
            }
            else {
                int m = lis(sol, 0, sol.size()-1,envelopes[i][1] );
                sol[m]=envelopes[i][1];
            }
        }


return sol.size();
        
    }
};
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