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Create constructBinaryTreePreorderInOrder.py

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	`1`	`+sample 355 ms submission`
	`2`	`+# Definition for a binary tree node.`
	`3`	`+# class TreeNode(object):`
	`4`	`+# def __init__(self, x):`
	`5`	`+# self.val = x`
	`6`	`+# self.left = None`
	`7`	`+# self.right = None`
	`8`	`+class Solution(object):`
	`9`	`+ def buildTree(self, preorder, inorder):`
	`10`	`+ """`
	`11`	`+ :type preorder: List[int]`
	`12`	`+ :type inorder: List[int]`
	`13`	`+ :rtype: TreeNode`
	`14`	`+ """`
	`15`	`+ # 若是len(preorder)為0 則返回空`
	`16`	`+ # 首次輸入邊界條件`
	`17`	`+ if len(preorder) == 0:`
	`18`	`+ return None`
	`19`	`+ # 遞歸edge`
	`20`	`+ # 若是長度為1 則返回當前值`
	`21`	`+ if len(preorder) == 1:`
	`22`	`+ return TreeNode(preorder[0])`
	`23`	`+ root = TreeNode(preorder[0])`
	`24`	`+ # 從preorder的第一個找出 inorder的index`
	`25`	`+ index = inorder.index(root.val)`
	`26`	`+`
	`27`	`+ # 記得切片不包括尾數左閉右開 -> [1:0]==[]`
	`28`	`+ root.left = self.buildTree(preorder[1:index+1], inorder[0:index])`
	`29`	`+ root.right = self.buildTree(preorder[index+1:], inorder[index+1:])`
	`30`	`+ return root`

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