CountingSorter.cs

usingSystem;
usingSystem.Collections.Generic;

usingAlgorithms.Common;

namespaceAlgorithms.Sorting
{
publicstaticclassCountingSorter
{
publicstaticvoidCountingSort(thisIList<int>collection)
{
if(collection==null||collection.Count==0)
return;

// Get the maximum number in array.
intmaxK=0;
intindex=0;
while(true)
{
if(index>=collection.Count)
break;

maxK=Math.Max(maxK,collection[index]+1);
index++;
}

// The array of keys, used to sort the original array.
int[]keys=newint[maxK];
keys.Populate(0);// populate it with zeros

// Assign the keys
for(inti=0;i<collection.Count;++i)
{
keys[collection[i]]+=1;
}

// Reset index.
index=0;

// Sort the elements
for(intj=0;j<keys.Length;++j)
{
varval=keys[j];

if(val>0)
{
while(val-->0)
{
collection[index]=j;
index++;
}
}
}
}
}
}