<p>You are given a 2D integer array <code>descriptions</code> where <code>descriptions[i] = [parent<sub>i</sub>, child<sub>i</sub>, isLeft<sub>i</sub>]</code> indicates that <code>parent<sub>i</sub></code> is the <strong>parent</strong> of <code>child<sub>i</sub></code> in a <strong>binary</strong> tree of <strong>unique</strong> values. Furthermore,</p>

<ul>
	<li>If <code>isLeft<sub>i</sub> == 1</code>, then <code>child<sub>i</sub></code> is the left child of <code>parent<sub>i</sub></code>.</li>
	<li>If <code>isLeft<sub>i</sub> == 0</code>, then <code>child<sub>i</sub></code> is the right child of <code>parent<sub>i</sub></code>.</li>
</ul>

<p>Construct the binary tree described by <code>descriptions</code> and return <em>its <strong>root</strong></em>.</p>

<p>The test cases will be generated such that the binary tree is <strong>valid</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2022/02/09/example1drawio.png" style="width: 300px; height: 236px;" />
<pre>
<strong>Input:</strong> descriptions = [[20,15,1],[20,17,0],[50,20,1],[50,80,0],[80,19,1]]
<strong>Output:</strong> [50,20,80,15,17,19]
<strong>Explanation:</strong> The root node is the node with value 50 since it has no parent.
The resulting binary tree is shown in the diagram.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2022/02/09/example2drawio.png" style="width: 131px; height: 300px;" />
<pre>
<strong>Input:</strong> descriptions = [[1,2,1],[2,3,0],[3,4,1]]
<strong>Output:</strong> [1,2,null,null,3,4]
<strong>Explanation:</strong> The root node is the node with value 1 since it has no parent.
The resulting binary tree is shown in the diagram.
</pre>

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

<ul>
	<li><code>1 &lt;= descriptions.length &lt;= 10<sup>4</sup></code></li>
	<li><code>descriptions[i].length == 3</code></li>
	<li><code>1 &lt;= parent<sub>i</sub>, child<sub>i</sub> &lt;= 10<sup>5</sup></code></li>
	<li><code>0 &lt;= isLeft<sub>i</sub> &lt;= 1</code></li>
	<li>The binary tree described by <code>descriptions</code> is valid.</li>
</ul>

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def createBinaryTree(self, descriptions: List[List[int]]) -> Optional[TreeNode]:
        
        d={}
        parent={}
        for i in descriptions:

            if i[0] not in d:
                temp=TreeNode()
                d[i[0]]=temp
                d[i[0]].val=i[0]

            
            if i[2]==1:
                d[i[0]].left=TreeNode()
                d[i[0]].left.val=i[1]
            if i[2]==0:
                d[i[0]].right=TreeNode()
                d[i[0]].right.val=i[1]

            parent[i[1]]=(i[0],"L" if i[2]==1 else "R")



        root=TreeNode()
        for i in d.keys():
            if i not in parent:
                root=d[i]

        
        nodes=len(d)
        def make(node):
            
            #print("yayaya",node)
            #print(node.left!=None and node.left.val in d)
            if node.left!=None and node.left.val in d:
                node.left=make(d[node.left.val])

            if node.right!=None and node.right.val in d:
                node.right=make(d[node.right.val])
            
            if (node.left!=None and node.left.val in d) ==0 and (node.right!=None and node.right.val in d) ==0:
                return d[node.val]

            return node

        root=make(root)

        return root

        


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