Leetcode 700 二叉搜索树中的搜索
思路:BST性质,爆搜
时间复杂度: O ( n ) O(n) O(n),最坏情况
空间复杂度: O ( n ) O(n) O(n),最坏情况
/**
* 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* searchBST(TreeNode* root, int val) {
if (!root) return nullptr;
else if (root->val == val) return root;
return searchBST(root->val > val ? root->left : root->right, val);
}
};