<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:
    def maxEnvelopes(self, envelopes: List[List[int]]) -> int:
        # [1,2] [2,3] [3, 4] [4,1][ 5,2][ 5,3], [5,4]
        for i in range(len(envelopes)):
            envelopes[i] = (envelopes[i][0], -envelopes[i][1])
        envelopes = list(set(envelopes))
        envelopes.sort()

        russian = []
        prevW = -1

        # print(envelopes)
        def find(dolls, h):
            left = 0
            right = len(dolls) - 1

            while left < right:
                mid = left + (right - left) // 2
                if dolls[mid][1] < h:
                    left = mid + 1
                else:
                    right = mid
            # print(dolls, h, left)
            return left if left < len(dolls) and dolls[left][1] >= h else None


        for envelope in envelopes:
            w, h = envelope
            h = -h

            if len(russian) == 0 or (h > russian[-1][1] and w > russian[-1][0]):
                russian.append([w, h])
                prevW = w
            elif find(russian, h) is not None:
                prevIdx = find(russian, h)
                russian[prevIdx] = [w, h]
                prevW = w

        return len(russian)
61000