【LEETCODE】108-Convert Sorted Array to Binary Search Tree

# 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, nums):
"""
:type nums: List[int]
:rtype: TreeNode
"""

if len(nums)==0:
return None
elif len(nums)==1:
return TreeNode(nums[0])
else:
mid=nums[len(nums)/2]             #找到nums的中位值，作为root
root=TreeNode(mid)
root.left=self.sortedArrayToBST(nums[0:len(nums)/2])                    #比中位值小的放在left子树
root.right=self.sortedArrayToBST(nums[len(nums)/2+1:len(nums)])         #比中位值大的放在right子树
return root