使用深度优先搜索来做
1 /**
2 * Definition for binary tree
3 * struct TreeNode {
4 * int val;
5 * TreeNode *left;
6 * TreeNode *right;
7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {}
8 * };
9 */
10 class Solution{
11 public:
12 TreeNode *sortedArrayToBST(vector<int>&num)
13 {
14 TreeNode *root=NULL;
15 if(num.size())
16 DFS(root,num,0,num.size()-1);
17 return root;
18 }
19 void DFS(TreeNode *(&root),vector<int> num,int low,int high)
20 {
21 int mid=(low+high)/2;
22 int value=num[mid];
23 root=new TreeNode(value);
24 if(low<mid)
25 DFS(root->left,num,low,mid-1);
26 if(high>mid)
27 DFS(root->right,num,mid+1,high);
28 }
29 };
