void swap(int index1, int index2)
{
ReaderAndNum temp = data[index1];
data[index1] = data[index2];
data[index2] = temp;
}
public static void Merge(ref List <StreamReader> readers, ref StreamWriter writer, int nodeRamSizeMb)
{
int sizeMb = FindWriteSize(readers.Count, nodeRamSizeMb);
int countNos = Helper.CountNosFitInSizeMb(sizeMb);
Heap heap = new Heap(readers.Count * countNos);
foreach (var reader in readers)
{
for (int i = 0; i < countNos; i++)
{
AddCurrentToHeap(reader, heap);
}
}
while (!heap.IsEmpty())
{
ReaderAndNum min = null;
int minsCount = 0;
string mins = "";
while (heap.GetMin(out min) && minsCount < countNos)
{
minsCount++;
mins += min.num + "\n";
AddCurrentToHeap(min.reader, heap);
}
writer.Write(mins);
}
}
/// <summary>
/// Most basic way to merge sorted files. Pick min from each file and take min from them.
/// Output the min to output file and pick the next min from the stream that current min got picked.
/// Complexity for n files of k size each: 0(n * n * k)
/// </summary>
/// <param name="readers"></param>
/// <param name="writer"></param>
public static void Merge(ref List <StreamReader> readers, ref StreamWriter writer)
{
List <ReaderAndNum> currentMins = new List <ReaderAndNum>();
// Create list of initial mins from each stream.
foreach (var reader in readers)
{
AddCurrentToArray(reader, currentMins);
}
//write min of all mins to file and get next min from that stream
while (true)
{
ReaderAndNum min = currentMins.First();
foreach (var pair in currentMins)
{
if (pair.num < min.num)
{
min = pair;
}
}
writer.WriteLine(min.num);
currentMins.Remove(min);
AddCurrentToArray(min.reader, currentMins);
if (!currentMins.Any())
{
break;
}
}
}
public bool Add(ReaderAndNum no)
{
if (currentIndex == Size)
{
return(false);
}
data[currentIndex] = no;
HeapifyBottomUp(currentIndex);
currentIndex++;
return(true);
}
public bool GetMin(out ReaderAndNum min)
{
min = null;
if (currentIndex == 0)
{
return(false);
}
min = data[0];
HeapifyRoot();
currentIndex--;
return(true);
}
public static void Merge(ref List <StreamReader> readers, ref StreamWriter writer)
{
Heap heap = new Heap(readers.Count);
foreach (var reader in readers)
{
AddCurrentToHeap(reader, heap);
}
while (!heap.IsEmpty())
{
ReaderAndNum min = null;
if (heap.GetMin(out min))
{
writer.WriteLine(min.num);
AddCurrentToHeap(min.reader, heap);
}
}
}
