leetcode 108 将有序数组转换为二叉搜索树 (Convert Sorted Array to Binary Search Tree)

/**
 * 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) {
        int len=nums.size();
        return soln(nums,0,len);
    }
    TreeNode* soln(vector<int>& nums,int bg,int ed) {
        int mid=bg+(ed-bg)/2;
        if(mid==ed){
            return NULL;
        }
        TreeNode *res=new TreeNode(nums[mid]);
        res->left=soln(nums,bg,mid);
        res->right=soln(nums,mid+1,ed);
        return res;
    }
};

View Code