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Merge pull request #3195 from thesouldev/main
Create: 0106-construct-binary-tree-from-inorder-and-postorder-traversal.py
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# Definition for a binary tree node.
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# class TreeNode:
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# def __init__(self, val=0, left=None, right=None):
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# self.val = val
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# self.left = left
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# self.right = right
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class Solution:
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def buildTree(self, inorder: List[int], postorder: List[int]) -> Optional[TreeNode]:
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def buildTreeHelper(left, right):
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if left > right:
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return None
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rootVal = postorder.pop()
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rootNode = TreeNode(rootVal)
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idx = inorderIndexMap[rootVal]
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rootNode.right = buildTreeHelper(idx + 1, right)
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rootNode.left = buildTreeHelper(left, idx - 1)
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return rootNode
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inorderIndexMap = {}
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for (i, val) in enumerate(inorder):
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inorderIndexMap[val] = i
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return buildTreeHelper(0, len(postorder) - 1)

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