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FactorGenerator.cs
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FactorGenerator.cs
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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Ckknight.ProjectEuler.Collections
{
public class FactorGenerator : IEnumerable<long>
{
public FactorGenerator(long number)
: this(number, true) { }
public FactorGenerator(long number, bool includeNumber)
{
if (number < 1)
{
throw new ArgumentOutOfRangeException("number", number, "Must be at least 1");
}
_number = number;
_includeNumber = includeNumber;
}
private readonly long _number;
private readonly bool _includeNumber;
#region IEnumerable<long> Members
public IEnumerator<long> GetEnumerator()
{
long[] primeFactors = new PrimeFactorGenerator(_number).ToArray();
var divisors = new Range(primeFactors.Length)
.Aggregate(new HashSet<long> { 1L }, (x, i) =>
{
long primeFactor = primeFactors[i];
x.UnionWith(x.Select(v => v * primeFactor).ToArray());
return x;
});
return divisors.GetEnumerator();
}
#endregion
#region IEnumerable Members
IEnumerator IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
#endregion
}
}