internal static RedBlackNode Add(System.Collections.IComparer comp, RedBlackNode t, object key, object val, Box found)
{
if (t is null)
{
return(val is null ? new RedNode(key) : new RedValueNode(key, val));
}
int c = comp.Compare(key, t.Key);
if (c == 0)
{
found.Value = t;
return(null);
}
var insert = c < 0 ? Add(comp, t.Left, key, val, found) : Add(comp, t.Right, key, val, found);
if (insert is null)
{
return(null);
}
return(c < 0
? t.AddLeft(insert)
: t.AddRight(insert));
}