653. Two Sum IV – Input is a BST

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
  public boolean findTarget(TreeNode root, int k) {
		ArrayList data = new ArrayList();
		traverers(root, data);
		for (int i  = 0 ; i < data.size() ; i++)
			for (int j  = 0 ; j < data.size() && i!=j ; j++)
				if (data.get(i) + data.get(j) == k)
					return true;

		return false;
	}

	private void traverers(TreeNode root, ArrayList data) {
		if (root != null) {
			data.add(root.val);
			traverers(root.left, data);
			traverers(root.right, data);
		}
	}
}