108. Convert Sorted Array to Binary Search Tree——tree
题目分析:二叉树的高度差不能超过1
class TreeNode(object): def __init__(self, x): self.val = x self.left = None self.right = None class Solution(object): def sortedArrayToBST(self, nums): def dfs(start, end): if start > end: return None middle = start+(end-start)//2 root = TreeNode(nums[middle]) root.left = dfs(start, middle-1) root.right = dfs(middle+1, end) return root if not nums: return None return dfs(0, len(nums)-1)