/**
 * 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 {
    private int max = 0;

    public int maxAncestorDiff(TreeNode root) {
        max = 0;
        maxDiffFinderMax(root);
        maxDiffFinderMin(root);
        return max;

    }

    public int maxDiffFinderMax(TreeNode root) {
        if (root != null) {
            int left = root.left == null ? root.val : maxDiffFinderMax(root.left);
            int right = root.right == null ? root.val : maxDiffFinderMax(root.right);
            max = Math.max(max, Math.abs(root.val - left));
            max = Math.max(max, Math.abs(root.val - right));
            return Math.max(root.val, Math.max(left, right));

        }
        return 0;
    }

    public int maxDiffFinderMin(TreeNode root) {
        if (root != null) {
            int left = root.left == null ? root.val : maxDiffFinderMin(root.left);
            int right = root.right == null ? root.val : maxDiffFinderMin(root.right);
            max = Math.max(max, Math.abs(root.val - left));
            max = Math.max(max, Math.abs(root.val - right));
            return Math.min(root.val, Math.min(left, right));

        }
        return 0;
    }
}