单选题库

#include <iostream>
using namespace std;
 
struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
 
TreeNode* search(TreeNode* root, int val) {
    cout << root->val << " ";
    if (root == NULL || root->val == val) return root;
 
    if (val < root->val)
        return search(root->left, val);
    else
        return search(root->right, val);
}

    5
   / \
  3   7
 / \ / \
2  4 6  8