思路

根据左右大小关系，寻找节点

代码

class Solution {
public:TreeNode* searchBST(TreeNode* root, int val) {if(root->val == val){return root;}if(root->val < val){if(root->right) return searchBST(root->right, val);}else{if(root->left) return searchBST(root->left, val);}return nullptr;}
};