private void Traverse(Bridge bridge)
{
CurrentLocation = bridge.Location;
foreach (var observer in _observers)
{
observer.NotifyLocationChanged();
}
//Only hikers whose starting location is before the bridge have to cross it.
List <Hiker> hikersTraversing = Hikers.Where(x => x.StartingLocation < bridge.Location).OrderBy(s => s.Speed).ToList();
//Make groups of up to 2 hikers. Pair slowest hikers together to save time.
List <List <Hiker> > hikerGroups = hikersTraversing.Select((x, idx) => new { x, idx })
.GroupBy(x => x.idx / 2)
.Select(g => g.Select(a => a.x).ToList()).ToList();
foreach (List <Hiker> group in hikerGroups)
{
MakeTrip(group, bridge);
}
BridgesCrossed.Add(bridge);
foreach (var observer in _observers)
{
observer.NotifyBridgeCrossed();
}
}
private void CheckForHikerExceptions()
{
if (Hikers == null)
{
throw new ArgumentNullException("No hikers found.");
}
if (!Hikers.Any(x => x.StartingLocation == 0))
{
throw new ArgumentException("No hikers at the start location.");
}
if (Hikers.Any(x => x.Speed <= 0))
{
throw new ArgumentException("Hiker found with non-positive speed.");
}
}
