public static IEnumerable <int> BreathFirstSearch(IEnumerable <int> starts, AdjacencyListGraph <long> graph)
{
var visited = new SearchData <bool>(graph.Size(), false);
var queue = new Queue <int>();
foreach (var start in starts)
{
visited.SetValue(start, false);
queue.Enqueue(start);
}
while (queue.Any())
{
var current = queue.Dequeue();
foreach (var neighbor in graph.NeighborIndexes(current).Where(i => i != current))
{
if (visited.Visited(neighbor))
{
continue;
}
queue.Enqueue(neighbor);
visited.SetValue(neighbor, true);
}
}
var visitedIndexes = visited.Values
.Select((v, i) => new { Visited = v, Index = i })
.Where(x => x.Visited)
.Select(x => x.Index);
return(visitedIndexes);
}
private void Explore(int start)
{
_visitedFrom = new SearchData <int>(_graph.Size(), -1);
_distance = new SearchData <int>(_graph.Size(), MaxDistance);
_distance.SetValue(start, 0);
//Make Prioirty Queue
var pq = new MinPriorityQueue <long>(_graph.Size(), long.MaxValue);
for (var i = 0; i < _distance.Length; i++)
{
pq.Enqueue(i, _distance.GetValue(i));
}
while (!pq.IsEmpty())
{
//Console.WriteLine("Queue: {0}", pq);
var currentIndex = pq.Dequeue();
//Console.WriteLine("Extract: {0}", currentIndex);
foreach (var edge in _graph.Neighbors(currentIndex))
{
var neighborIndex = edge.Right;
var d = _distance.GetValue(neighborIndex);
var dFromC = _distance.GetValue(currentIndex) == MaxDistance
? MaxDistance
: _distance.GetValue(currentIndex) + (int)edge.Weight;
//Console.WriteLine("Edge {1} => {0} : Distance {2} : {3}",neighborIndex,currentIndex,dFromC,d);
if (d <= dFromC)
{
continue;
}
//Set New Distance Values
_distance.SetValue(neighborIndex, dFromC);
_visitedFrom.SetValue(neighborIndex, currentIndex);
pq.ChangePriority(neighborIndex, dFromC);
}
}
}
