LeetCode题解之 Convert Sorted Array to Binary Search Tree

1、题目描述

2、问题分析

使用二分法即可。

3、代码

TreeNode* sortedArrayToBST(vector<int>& nums) {
        if (nums.size() == 0)
            return NULL;
        
        int left = 0;
        int right = nums.size() - 1;
        
        TreeNode *node = new TreeNode(0);
        BST(node->left,nums, left, right);
        return node->left;
        
        
        
    }
    
    void BST(TreeNode   * &parent, vector<int> &nums,int left, int right)
    {
        
        if (left <= right) {
            int mid = (left + right)/2;
            TreeNode *node = new TreeNode(nums[mid]);
            parent = node;
            BST(node->left, nums, left, mid - 1);
            BST(node->right, nums, mid + 1, right);
        } else {
            return ;
        }
    }