private static ITwoThree <T> RedistributeRight(T first, T second, ITwoThree <T> left, ITwoThree <T> middle, ITwoThree <T> right)
{
// Case A
if (left is TwoNode <T> && middle is TwoNode <T> )
{
var sm = (TwoNode <T>)middle;
var l = left;
var r = new ThreeNode <T>(sm.Value, second, sm.Left, sm.Right, right);
return(new TwoNode <T>(first, l, r));
}
// Case B
if (middle is ThreeNode <T> )
{
var sm = (ThreeNode <T>)middle;
var l = left;
var m = new TwoNode <T>(sm.First, sm.Left, sm.Middle);
var r = new TwoNode <T>(second, sm.Right, right);
return(new ThreeNode <T>(first, sm.Second, l, m, r));
}
// Case C
if (left is ThreeNode <T> && middle is TwoNode <T> )
{
var sl = (ThreeNode <T>)left;
var sm = (TwoNode <T>)middle;
var l = new TwoNode <T>(sl.First, sl.Left, sl.Middle);
var m = new TwoNode <T>(first, sl.Right, sm.Left);
var r = new TwoNode <T>(second, sm.Right, right);
return(new ThreeNode <T>(sl.Second, sm.Value, l, m, r));
}
throw new InvalidOperationException();
}
private static ITwoThree <T> RedistributeMiddle(T first, T second, ITwoThree <T> left, ITwoThree <T> middle, ITwoThree <T> right)
{
// Case A
if (left is TwoNode <T> && right is TwoNode <T> )
{
var sl = (TwoNode <T>)left;
var l = new ThreeNode <T>(sl.Value, first, sl.Left, sl.Right, middle);
var r = right;
return(new TwoNode <T>(second, l, r));
}
// Case B
if (right is ThreeNode <T> )
{
var sr = (ThreeNode <T>)right;
var l = left;
var m = new TwoNode <T>(second, middle, sr.Left);
var r = new TwoNode <T>(sr.Second, sr.Middle, sr.Right);
return(new ThreeNode <T>(first, sr.First, l, m, r));
}
// Case C
if (left is ThreeNode <T> && right is TwoNode <T> )
{
var sl = (ThreeNode <T>)left;
var l = new TwoNode <T>(sl.First, sl.Left, sl.Middle);
var m = new TwoNode <T>(first, sl.Right, middle);
var r = right;
return(new ThreeNode <T>(sl.Second, second, l, m, r));
}
throw new InvalidOperationException();
}