public static void Sum(Id i1, Id i2)
{
// this becomes the sum between i1 and i2
//sum(0, X) -> X;
//sum(X, 0) -> X;
//sum({L1,R1}, {L2, R2}) -> norm_id({sum(L1, L2), sum(R1, R2)}).
if (i1.IsLeaf
&& i1.Value == 0)
{
i1.Copy(i2);
return;
}
if (i2.IsLeaf
&& i2.Value == 0)
{
return;
//i1 is the result
}
if (!i1.IsLeaf
&& !i2.IsLeaf)
{
Sum(i1.Left, i2.Left);
Sum(i1.Right, i2.Right);
i1.Normalize();
return;
}
throw new IdOperationException("Sum failed", i1, i2);
}
