public static void Test()
{
Solution s = new Solution();
int?[] t1 = new int?[] { 1, 2, 3, null, 4, null, 5 };
TreeNode root = new TreeNode(t1[0].GetValueOrDefault());
ProduceTreeNode(t1, t1.Length, 0, root);
Console.WriteLine(s.IsCousins(root, 5, 3));
}