LeetCode: 108. Convert Sorted Array to Binary Search Tree

题目

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

Example:

Given the sorted array: [-10,-3,0,5,9], One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BST: 0 / \ -3 9 / / -10 5

解题思路

取数组的中位数处理，分左右两个节点依次递归就好

# Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution: def sortedArrayToBST(self, nums: List[int]) -> TreeNode: if len(nums)==0: return None l=int(len(nums)/2) root = TreeNode(nums[l]) root.left = self.sortedArrayToBST(nums[:l]) root.right = self.sortedArrayToBST(nums[l+1:]) return root