void Leagalize()
{
while (stack.Count > 0)
{
var s = stack.Pop();
if (FindNodes(s, out DN n1, out DN n2))
{
var p1 = n1.triangle.RemainingPoint(s);
var p2 = n2.triangle.RemainingPoint(s);
if (n1.triangle.GetCircumscribledCircle().Contains(p2))
{
var o = DN.Flip(n1, n2, s, p1, p2);
stack.Push(o.s1);
stack.Push(o.s2);
stack.Push(o.s3);
stack.Push(o.s4);
nodes.Remove(n1);
nodes.Remove(n2);
nodes.Add(o.n1);
nodes.Add(o.n2);
}
}
}
}