protected override void Solve(out string answer)
{
var testedRange = Enumerable.Range(1, 28123).AsParallel();
long summator = 0;
//Parallel.ForEach()
testedRange.ForAll(number =>
{
NumberDivisor numberDivisor = new NumberDivisor();
bool hasBeenWrittenAsSumOfTwoAbundantNumbers = false; //Will be set to true only if at least one sum can be expressed using abundant numbers.
long midpoint = (number / 2) + 1;
for (int i = 1; i <= midpoint; i++)
{
#region Get left and right portions of the number in all combinations
var left = i;
var right = number - left;
#endregion
var leftAbundancyType = numberDivisor.IsAbundantOrDeficientOrPerfect(left);
var rightAbundancyType = numberDivisor.IsAbundantOrDeficientOrPerfect(right);
if (leftAbundancyType == AbundancyType.Abundant && rightAbundancyType == AbundancyType.Abundant)
{
hasBeenWrittenAsSumOfTwoAbundantNumbers = true;
break;
}
}
if (!hasBeenWrittenAsSumOfTwoAbundantNumbers)
{
lock (this) summator += number; //Increase the sum if combination of 2 abundant numbers could not be found.
}
});
answer = string.Format("Sum of all the positive integers which cannot be written as the sum of two abundant numbers is {0}.", summator);
}
protected override void Solve(out string answer)
{
NumberDivisor numberDivisor = new NumberDivisor();
long n = 220;
long f = numberDivisor.CalculateSumOfProperDivisors(n);
Answer = f.ToString();
Dictionary <long, long> mapOfNumbersToDivisors = new Dictionary <long, long>();
// Identify the list of all d() functions under 10000.
foreach (int number in Enumerable.Range(1, 10000))
{
long dFunction = numberDivisor.CalculateSumOfProperDivisors(number);
mapOfNumbersToDivisors.Add(number, dFunction);
}
//mapOfNumbersToDivisors.Add(220, d(220));
//mapOfNumbersToDivisors.Add(284, d(284));
List <long> amicableNumbers = new List <long>();
// Find the amicable numbers
mapOfNumbersToDivisors.AsParallel().ForAll(mapEntry =>
{
long key = mapEntry.Key;
if (amicableNumbers.Contains(key))
{
return; // Make sure we do not count the same amicable number twice.
}
long value = mapEntry.Value;
try
{
long reverseKey = mapOfNumbersToDivisors[value];
if (key == reverseKey) //Key and value are the two amicable numbers. Add them to the list to remember.
{
if (key != value) //amicability requires that d(a) = b and d(b) = a, where a != b
{
amicableNumbers.Add(key);
amicableNumbers.Add(value);
}
}
}
catch (KeyNotFoundException e)
{
//There is no reverse value in the collection, so no chance of amicability.
string m = e.Message;
}
});
var sumOfAmicableNumbers = amicableNumbers.Sum();
answer = string.Format("The sum of all the amicable numbers under 10000 is {0}.", sumOfAmicableNumbers);
}
public void TestPerfects()
{
DateTime start = DateTime.Now;
long temp = 28;
NumberDivisor numberDivisor = new NumberDivisor();
var sumDivisors = numberDivisor.CalculateSumOfProperDivisors(temp);
var is28Abundant = numberDivisor.IsAbundantOrDeficientOrPerfect(temp);
var is12Abundant = numberDivisor.IsAbundantOrDeficientOrPerfect(12);
var is57Abundant = numberDivisor.IsAbundantOrDeficientOrPerfect(57);
var elapsedTime = DateTime.Now - start;
var sb = new StringBuilder();
sb.AppendFormat("Elapsed computation time: {0}. Sum of properDivisors of {1} = {2}.", elapsedTime, temp, sumDivisors); sb.AppendLine();
sb.AppendFormat("Number {0} is {1}.", temp, is28Abundant); sb.AppendLine();
sb.AppendFormat("Number {0} is {1}.", 12, is12Abundant); sb.AppendLine();
sb.AppendFormat("Number {0} is {1}.", 57, is57Abundant); sb.AppendLine();
Answer = sb.ToString();
}
