<p>Given two integer arrays <code>preorder</code> and <code>inorder</code> where <code>preorder</code> is the preorder traversal of a binary tree and <code>inorder</code> is the inorder traversal of the same tree, construct and return <em>the binary tree</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/tree.jpg" style="width: 277px; height: 302px;" />
<pre>
<strong>Input:</strong> preorder = [3,9,20,15,7], inorder = [9,3,15,20,7]
<strong>Output:</strong> [3,9,20,null,null,15,7]
</pre>

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

<pre>
<strong>Input:</strong> preorder = [-1], inorder = [-1]
<strong>Output:</strong> [-1]
</pre>

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

<ul>
	<li><code>1 &lt;= preorder.length &lt;= 3000</code></li>
	<li><code>inorder.length == preorder.length</code></li>
	<li><code>-3000 &lt;= preorder[i], inorder[i] &lt;= 3000</code></li>
	<li><code>preorder</code> and <code>inorder</code> consist of <strong>unique</strong> values.</li>
	<li>Each value of <code>inorder</code> also appears in <code>preorder</code>.</li>
	<li><code>preorder</code> is <strong>guaranteed</strong> to be the preorder traversal of the tree.</li>
	<li><code>inorder</code> is <strong>guaranteed</strong> to be the inorder traversal of the tree.</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 buildTree(self, preorder: List[int], inorder: List[int]) -> Optional[TreeNode]:
        # preorder: root left right
        # inorder: left root right
        n = len(inorder)
        mpre = {preorder[i]:i for i in range(n)}
        mpin = {inorder[i]:i for i in range(n)}
        
        def construct(a,b,p,q):
            # print(a,b,p,q)
            if a>b or p>q:
                return None
            if a==b:
                return TreeNode(val=preorder[a])
            root = preorder[a]
            node = TreeNode(val=root)
            idxin = mpin[root]
            # print(idxin)

            pleft,qleft = p,idxin-1
            pright,qright = idxin+1,q
            # left1,left2 = inorder[pleft],inorder[qleft]
            # right1,right2 = inorder[pright],inorder[qright]
            # aleft,bleft = mpre[left1],mpre[left2]
            # aright,bright = mpre[right1],mpre[right2]
            aleft,bleft = a+1,qleft-pleft+a+1
            aright,bright = max(a+1,bleft+1),b
            
            node.left = construct(aleft,bleft,pleft,qleft)
            node.right = construct(aright,bright,pright,qright)
            return node
        root = construct(0,n-1,0,n-1)
        return root
19334