【leetcode刷题】T120-将有序数组转换为二叉搜索树

示例:
给定有序数组: [-10,-3,0,5,9],
一个可能的答案是：[0,-3,9,-10,null,5]，它可以表示下面这个高度平衡二叉搜索树：
      0
     / \
   -3   9
   /   /
 -10  5

# 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
        place = len(nums) // 2
        root = TreeNode(nums[place])
        root.left = self.sortedArrayToBST(nums[:place])
        root.right = self.sortedArrayToBST(nums[place+1:])
        return root

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* sortedArrayToBST(vector<int>& nums) {
        if(nums.size() == 0)
            return NULL;
        int place = nums.size() / 2;
        TreeNode* root = new TreeNode(nums[place]);
        vector<int> num1(nums.begin(), nums.begin()+place);
        root->left = sortedArrayToBST(num1);
        vector<int> num2(nums.begin()+place+1, nums.end());
        root->right = sortedArrayToBST(num2);
        return root;
    }
};