public int Compare(Journey <T> x, Journey <T> y)
{
// we walk through both journeys until we reach a 'Transfer'
// We compare, the one with the most important station wins
// If they are equal, we continue to the next transfer
do
{
while (x.PreviousLink != null && !x.Location.Equals(x.PreviousLink.Location))
{
x = x.PreviousSpecial();
}
while (y.PreviousLink != null && !y.Location.Equals(y.PreviousLink.Location))
{
y = y.PreviousSpecial();
}
if (x.PreviousLink == null && y.PreviousLink == null)
{
// We've found the root, this is a tie
return(_xWins);
}
if (x.PreviousLink == null || y.PreviousLink == null)
{
// One of them reached the end while the other didn't...
// This is not a family
throw new ArgumentException(
$"Can not compare two journeys with a different number of transfers:\n{x.ToString(50)}\n{y.ToString(50)}");
}
// Both x and y are at a transfer
// Which one is better?
_importances.TryGetValue(x.Location, out var xi);
_importances.TryGetValue(x.Location, out var yi);
if (xi > yi)
{
return(_xWins);
}
if (yi < xi)
{
return(_yWins);
}
if (xi == yi)
{
x = x.PreviousLink;
y = y.PreviousLink;
}
} while (x.PreviousLink != null && y.PreviousLink != null);
return(_xWins);
}
