public async Task Merge(List <string> sortedChunks)
{
await Task.Yield();
var readers = new List <StreamReader>();
try
{
readers.AddRange(sortedChunks.Select(partition => new StreamReader(partition)));
foreach (var reader in readers)
{
var record = RecordSerializer.Deserialize(reader.ReadLine());
_queue.Enqueue(new FileRecord(reader, record));
}
while (_queue.Any())
{
var smallest = _queue.Dequeue();
await _sortedRecords.SendAsync(smallest.Record);
var newRecord = smallest.File.ReadLine();
if (newRecord == null)
{
continue;
}
var next = RecordSerializer.Deserialize(newRecord);
_queue.Enqueue(new FileRecord(smallest.File, next));
}
}
finally
{
foreach (var reader in readers)
{
reader.Dispose();
}
_sortedRecords.Complete();
}
}
private static long Distance(List <List <int> > adj, List <List <int> > cost, int s, int t)
{
var distances = Enumerable.Range(0, adj.Count).Select(_ => long.MaxValue).ToList();
var parents = Enumerable.Range(0, adj.Count).Select(_ => - 1).ToList();
var priorityQueue = new MinHeap <Tuple <int, long> >(new VertexDistanceComparer());
var startVertex = s;
distances[startVertex] = 0;
priorityQueue.Add(new Tuple <int, long>(startVertex, distances[startVertex]));
while (priorityQueue.Any())
{
var currentTuple = priorityQueue.ExtractDominating();
var currentVertex = currentTuple.Item1;
var currentVertexDistance = distances[currentVertex];
var adjVertices = adj[currentVertex];
var adjVerticesCosts = cost[currentVertex];
for (var i = 0; i < adjVertices.Count; i++)
{
var adjVertex = adjVertices[i];
var adjVertexWeight = adjVerticesCosts[i];
var distance = currentVertexDistance + adjVertexWeight;
if (distance < distances[adjVertex])
{
distances[adjVertex] = distance;
parents[adjVertex] = currentVertex;
priorityQueue.Add(new Tuple <int, long>(adjVertex, distance));
}
}
}
return(distances[t] < int.MaxValue ? distances[t] : -1);
}
