[LeetCode]题解（python）：109-Convert Sorted List to Binary Search Tree

题目来源：

　　https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/

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题意分析：

　　给定一个排好序的链表，将这个链表转换成一个高度平衡树。

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题目思路：

　　有一个偷懒的方法，将链表转换成一个数组，然后用上一题的解法解决。

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代码（python）：

　　

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def sortedListToBST(self, head):
        """
        :type head: ListNode
        :rtype: TreeNode
        """
        def sortedarray(nums):
            size = len(nums)
            if size == 0:
                return None
            if size == 1:
                return TreeNode(nums[0])
            size //= 2
            root = TreeNode(nums[size])
            root.left = sortedarray(nums[:size])
            root.right = sortedarray(nums[size + 1:])
            return root
        nums = []
        while head != None:
            nums.append(head.val)
            head = head.next
        return sortedarray(nums)