[Leetcode]@python 109. Convert Sorted List to Binary Search Tree

题目链接

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

题目原文

Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.

题目大意

给定一个已排序的链表，构建高度平衡的二叉树

解题思路

将链表存入数组，用上一次的解法

代码

# 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 sortedArrayToBST(self, array):
        l = len(array)
        if l == 0:
            return None
        if l == 1:
            return TreeNode(array[0])
        root = TreeNode(array[l // 2])
        root.left = self.sortedArrayToBST(array[:l // 2])
        root.right = self.sortedArrayToBST(array[l // 2 + 1])
        return root

class Solution(object):
    def sortedListToBST(self, head):
        """
        :type head: ListNode
        :rtype: TreeNode
        """
        array = []
        tmp = head
        while tmp:
            array.append(tmp.val)
            tmp = tmp.next

        return self.sortedArrayToBST(array)