105. construct binary tree from preorder and inorder traversal

Medium

https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/

Given preorder and inorder traversal of a tree, construct the binary tree.

Note:
You may assume that duplicates do not exist in the tree.

For example, given

1 2	preorder = [3,9,20,15,7] inorder = [9,3,15,20,7]

Return the following binary tree:

2019.9.3 独立做出来了

方法：

class (object):
    def buildTree(self, preorder, inorder):
        """
        :type preorder: List[int]
        :type inorder: List[int]
        :rtype: TreeNode
        """
        if len(preorder)==0:
            return None
        if len(preorder)==1:
            return TreeNode(preorder[0])
        node = TreeNode(preorder[0])
        for i in range(len(inorder)):
            if inorder[i]==preorder[0]:
                break
        node.left = self.buildTree(preorder[1:i+1], inorder[:i])
        node.right = self.buildTree(preorder[i+1:], inorder[i+1:])
        return node

类似题目：

Construct Binary Tree from Inorder and Postorder Traversal

105. construct binary tree from preorder and inorder traversal

近期文章

近期评论

标签

热门

文章归档

分类目录

功能