109 convert sorted list to binary search tree
109. Convert Sorted List to Binary Search Tree
题目: https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/
难度:
Medium
思路：
跟第 108 题一样
class Solution(object):
def sortedListToBST(self, head):
"""
:type head: ListNode
:rtype: TreeNode
"""
def sortedArrayToBST(nums):
if not nums:
return None
if nums:
mid = len(nums) / 2
root = TreeNode(nums[mid])
root.left = sortedArrayToBST(nums[:mid])
root.right = sortedArrayToBST(nums[mid+1:])
return root
if not head:
return None
else:
lst = []
while head:
lst.append(head.val)
head = head.next
return sortedArrayToBST(lst)
