LeetCode: Convert Sorted Array to Binary Search Tree

LeetCode: Convert Sorted Array to Binary Search Tree

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

地址：https://oj.leetcode.com/problems/convert-sorted-array-to-binary-search-tree/

算法：应该没什么难度，比把有序的链表转化为二叉搜索树要简单。代码：

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