LeetCode 108. 【递归】将有序数组转化成二叉搜索树
原题链接
简单
作者:
大明湖的鱼
,
2021-01-20 18:43:37
,
所有人可见
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阅读 423
/**
* 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:
//这种区间分治的题,用左闭右闭就好,左闭右开不方便,
//另外需要注意的是,求中点的溢出问题
TreeNode* sortedArrayToBST(vector<int>& nums) {
return help(nums,0,nums.size()-1);
}
TreeNode* help(vector<int>& nums,int l,int r){
if(r<l) return nullptr;
int mid = l + ((r-l)>>1);
TreeNode* root = new TreeNode(nums[mid]);
root->left = help(nums,l,mid-1);
root->right = help(nums,mid+1,r);
return root;
}
};