leetcode日记（95）将有序数组转换为二叉搜索树

很简单，感觉自己越来越适应数据结构题目了……

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    TreeNode* sortedArrayToBST(vector<int>& nums) {
        TreeNode* tree=new TreeNode(nums[nums.size()/2]);
        vector<int> left(nums.begin(),nums.begin()+nums.size()/2);
        vector<int> right(nums.begin()+nums.size()/2+1,nums.end());
        tree->left=sortedArrayToBST(left);
        tree->right=sortedArrayToBST(right);
        return tree;
    }
};