[LeetCoed] BST - Search in a Binary Search Tree

 

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    
    TreeNode result = null;
    
    public TreeNode searchBST(TreeNode root, int val) {        
        inorder(root, val);
        return result;
    }  
    
    public void inorder(TreeNode node, int target) {
		if(node != null) {
			inorder(node.left, target);
			if(node.val == target) {
                		result = node;
            		}
			inorder(node.right, target);
		}
	}
}

 

 

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public TreeNode searchBST(TreeNode root, int val) {
        TreeNode result = null;
        
        if(root.val == val) {
            return root;
        }
        
        if(root.val > val && root.left != null) {
            result = searchBST(root.left, val);
        }else if (root.val < val && root.right != null){
            result = searchBST(root.right, val);
        }
        return result;
    }
}