LeetCode700. 二叉搜索树中的搜索

题目

简单递归

 1 class Solution {
 2 public:
 3     TreeNode* searchBST(TreeNode* root, int val) {
 4         if(!root) return NULL;
 5         TreeNode* p;
 6         if(root->val == val) return root;
 7         if(root->val > val) p = searchBST(root->left,val);
 8         if(root->val < val) p = searchBST(root->right,val);
 9         return p;
10     }
11 };

迭代

 1 class Solution {
 2 public:
 3     TreeNode* searchBST(TreeNode* root, int val) {
 4         while(root!=NULL){
 5             if(root->val == val) return root;
 6             else if(root->val > val) root = root->left;
 7             else root = root->right;
 8         }
 9         return NULL;
10     }
11 };