private static int[] Helper(LeetCode549TreeNode root)
{
if (root == null)
{
return new int[] { 0, 0 }
}
;
var inr = 1;
var dcr = 1;
if (root.left != null)
{
var l = Helper(root.left);
if (root.val == root.left.val + 1)
{
dcr = l[1] + 1;
}
else if (root.val == root.left.val - 1)
{
inr = l[0] + 1;
}
}
if (root.right != null)
{
var r = Helper(root.right);
if (root.val == root.right.val + 1)
{
dcr = Math.Max(dcr, r[1] + 1);
}
else if (root.val == root.right.val - 1)
{
inr = Math.Max(inr, r[0] + 1);
}
}
_maxVal = Math.Max(_maxVal, dcr + inr - 1);
return(new int[] { inr, dcr });
}
}
public static int LongestConsecutive(LeetCode549TreeNode root)
{
return(_maxVal);
}
public LeetCode549TreeNode(int val = 0, LeetCode549TreeNode left = null, LeetCode549TreeNode right = null)
{
this.val = val;
this.left = left;
this.right = right;
}