public InversionCount MergeInversion(int[] left, int[] right)
{
InversionCount icTemp = new InversionCount();
List <int> SortedList = new List <int>();
var leftList = left.ToList <int>();
var rightList = right.ToList <int>();
while (leftList.Count > 0 || rightList.Count > 0)
{
if (leftList.Count > 0 && rightList.Count > 0)
{
if (leftList.First <int>() > rightList.First <int>())
{
SortedList.Add(rightList.First <int>());
rightList.Remove(rightList.First <int>());
foreach (var item in leftList)
{
icTemp.inversionCount++;
}
}
else
{
SortedList.Add(leftList.First <int>());
leftList.Remove(leftList.First <int>());
}
}
else if (leftList.Count == 0)
{
SortedList.Add(rightList.First <int>());
rightList.Remove(rightList.First <int>());
}
else if (rightList.Count == 0)
{
SortedList.Add(leftList.First <int>());
rightList.Remove(leftList.First <int>());
}
}
icTemp.sortedArray = SortedList.ToArray();
return(icTemp);
}
public InversionCount SortCount(int[] a)
{
InversionCount ic = new InversionCount();
List <int> firsthalf = new List <int>();
List <int> secondhalf = new List <int>();
int middle = a.Length / 2;
if (a.Length == 1)
{
return(ic = new InversionCount {
sortedArray = a, inversionCount = 0
});
}
else
{
for (int i = 0; i < middle; i++)
{
firsthalf.Add(a[i]);
}
for (int j = middle; j < a.Length; j++)
{
secondhalf.Add(a[j]);
}
var ic1 = SortCount(firsthalf.ToArray());
ic.inversionCount += ic1.inversionCount;
var ic2 = SortCount(secondhalf.ToArray());
ic.inversionCount += ic2.inversionCount;
var ic3 = MergeInversion(ic1.sortedArray, ic2.sortedArray);
ic3.inversionCount += ic.inversionCount;
return(ic3);
}
}