public static void Helper(LeetCode102TreeNode root, int level)
{
if (root == null)
{
return;
}
if (level == ans.Count)
{
ans.Add(new List <int>());
}
ans[level].Add(root.val);
if (root.left != null)
{
Helper(root.left, level + 1);
}
if (root.right != null)
{
Helper(root.right, level + 1);
}
}
public static IList <IList <int> > LevelOrder(LeetCode102TreeNode root)
{
Helper(root, 0);
return(ans);
}
public LeetCode102TreeNode(int val = 0, LeetCode102TreeNode left = null, LeetCode102TreeNode right = null)
{
this.val = val;
this.left = left;
this.right = right;
}
