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108_convert_sorted_array_to_binary_search_tree.py
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108_convert_sorted_array_to_binary_search_tree.py
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#!/usr/bin/python
# -*- coding: utf-8 -*-
#author : zhangdawang
#data: 2017-4-26
#difficulty degree:
#problem: 108_convert_sorted_array_to_binary_search_tree
#time_complecity:
#space_complecity:
#beats:
class TreeNode(object):
def __init__(self, x):
self.val = x
self.left = None
self.right = None
def CreateTree(self, tree, nums, i):
if i >= len(nums) // 2:
return
if nums[2 * i] != 0:
tree.left = TreeNode(nums[2 * i])
self.CreateTree(tree.left, nums, 2*i)
if nums[2 * i + 1] != 0:
tree.right = TreeNode(nums[2 * i + 1])
self.CreateTree(tree.right, nums, 2*i + 1)
def GenerateTree(self, nums):
root = TreeNode(nums[1])
self.CreateTree(root, nums, 1)
return root
class Solution(object):
def sortedArrayToBST(self, nums):
def dfs(nums, start, end):
if start > end: return None
mid = (start + end)//2
newnode = TreeNode(nums[mid])
newnode.left = dfs(nums, start, mid - 1)
newnode.right = dfs(nums, mid + 1, end)
return newnode
root = dfs(nums, 0, len(nums) - 1)
return root
nums = [1,3]
solute = Solution()
root = solute.sortedArrayToBST(nums)
print(root.left.val)