[leetcode] 108. Convert Sorted Array to Binary Search Tree 解题报告

题目链接：https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

思路：前面有一题将有序链表转换为平衡二叉搜索树的，思路都一样，递归的二分数组，取数组中间的一个数为根，左边的为左子树，右边的为右子树。

今天去看了一场昆汀的电影，叫什么来着《The Hateful Eight》没有字幕，看着好蛋疼啊，睡了前半段，到最后也没搞明白这电影讲的啥，只记得各种爆头


代码如下：

/**
* 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* convert(vector<int>& nums, int start, int end)
{
if(start > end) return NULL;
int mid = (start+end+1)/2;
TreeNode* root = new TreeNode(nums[mid]);
root->left = convert(nums, start, mid-1);
root->right = convert(nums, mid+1,end);
return root;
}
TreeNode* sortedArrayToBST(vector<int>& nums) {
int len = nums.size();
if(len == 0) return NULL;
return convert(nums, 0, len-1);
}
};