leetcode993

public class Node
    {
        public int CurNode;
        public int FatherNode;
        public int Layer;
    }

    public class Solution
    {
        public List<Node> L = new List<Node>();
        public void FrontTraversal(TreeNode root, int layer = 0)
        {
            if (root != null)
            {
                if (!L.Any())
                {
                    L.Add(new Node() { CurNode = root.val, FatherNode = 0, Layer = layer });
                }
                if (root.left != null)
                {
                    L.Add(new Node() { CurNode = root.left.val, FatherNode = root.val, Layer = layer + 1 });
                    FrontTraversal(root.left, layer + 1);
                }
                if (root.right != null)
                {
                    L.Add(new Node() { CurNode = root.right.val, FatherNode = root.val, Layer = layer + 1 });
                    FrontTraversal(root.right, layer + 1);
                }
            }

        }

        public bool IsCousins(TreeNode root, int x, int y)
        {
            FrontTraversal(root);
            var nodeX = L.Find(c => c.CurNode == x);
            var nodeY = L.Find(c => c.CurNode == y);
            if (nodeX != null && nodeY != null
                && nodeX.FatherNode != nodeY.FatherNode
                && nodeX.Layer == nodeY.Layer)
            {
                return true;
            }
            return false;
        }
    }