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 = )
         {
             if (root != null)
             {
                 if (!L.Any())
                 {
                     L.Add(new Node() { CurNode = root.val, FatherNode = , Layer = layer });
                 }
                 if (root.left != null)
                 {
                     L.Add(new Node() { CurNode = root.left.val, FatherNode = root.val, Layer = layer +  });
                     FrontTraversal(root.left, layer + );
                 }
                 if (root.right != null)
                 {
                     L.Add(new Node() { CurNode = root.right.val, FatherNode = root.val, Layer = layer +  });
                     FrontTraversal(root.right, layer + );
                 }
             }

         }

         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;
         }
     }