563. Binary Tree Tilt
public class Solution {
int result = 0;
public int findTilt(TreeNode root) {
postOrder(root);
return result;
}
private int postOrder(TreeNode root) {
if (root == null) return 0;
int left = postOrder(root.left);
int right = postOrder(root.right);
result += Math.abs(left - right);
return left + right + root.val;
}
}