Search in a Binary Search Tree — C++

// Time:  O(h)
// Space: O(1)

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* searchBST(TreeNode* root, int val) {
        while (root && val != root->val) {
            if (val < root->val) {
                root = root->left;
            } else {
                root = root->right;
            }
        }
        return root;
    }
};