/// <summary>
/// Get permutations of a list of chars
/// </summary>
/// <param name="list"></param>
public static List<string> GetPermutations(char[] list)
{
var rawPermutations = new Permutations<char>(list);
var permutations = rawPermutations.Select(chars => string.Join("", chars));
return permutations.ToList();
}
public override void Run()
{
var set = "123456789";
var len = set.Length;
int max = 0;
while (len > 0)
{
var matches = new List <int>();
var perm = new Permutations <char>(set.Take(len).ToList());
foreach (IEnumerable <char> digits in perm)
{
var n = Convert.ToInt32(string.Join("", digits));
if (math.isPrime(n))
{
max = Math.Max(n, max);
}
}
--len;
}
Console.WriteLine(max);
}
public static IEnumerable <IList <int> > Permutations(this IEnumerable <int> set)
{
var perm = new Permutations(set);
while (perm.GetNextPerm())
{
yield return(perm.Set);
}
}
public static HashSet <long> Generate(int nDigit)
{
var numbers = Enumerable.Range(1, nDigit);
var numberString = string.Empty;
foreach (var number in numbers)
{
numberString += number;
}
return(Permutations.Generate(long.Parse(numberString)));
}
public override void Run()
{
var digits = "0123456789";
var perm = new Permutations <char>(digits.ToList());
var values = perm
.Select(p => Convert.ToInt64(string.Join("", p)))
.OrderBy(i => i)
.ToArray();
Console.WriteLine(values[1000000 - 1]);
}
public void SetData()
{
char[] chars = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
Permutations<Char> perms = new Permutations<Char> (chars);
foreach (IList<Char> p in perms)
{
StringBuilder b = new StringBuilder ();
b.AppendFormat ("{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8],
p[9]);
data.Add (b.ToString ());
}
}
public void Permutations_SetWith3Elements_5PermutationsShoudBeReturned()
{
var perm = new Permutations(new[] { 1, 2, 3 });
var res = new List <string>();
while (perm.GetNextPerm())
{
res.Add(perm.Set.Select(i => i.ToString(CultureInfo.InvariantCulture)).Aggregate((a, b) => a + b));
}
Assert.IsTrue(res.Count == 5);
Assert.IsTrue(res.Contains("132"));
Assert.IsTrue(res.Contains("213"));
Assert.IsTrue(res.Contains("231"));
Assert.IsTrue(res.Contains("312"));
Assert.IsTrue(res.Contains("321"));
}
public override long Solve()
{
long circularPrimeCount = 0;
var primesLookup = Primes.CalculatePrimesBelow(max);
foreach (var prime in primesLookup)
{
if (PossibleCircularPrime(prime))
{
var rotations = Permutations.GenerateNumberRotations(prime);
if (rotations.All(p => primesLookup.Contains(p)))
{
circularPrimeCount++;
}
}
}
return(circularPrimeCount);
}
public static HashSet <long> GenerateZeroToN(int nDigit)
{
var numbers = Enumerable.Range(1, nDigit).ToList();
//append 0 at end so cast to long doesn't chop it off
numbers.Add(0);
var numberString = string.Empty;
foreach (var number in numbers)
{
numberString += number;
}
var pandigitals = Permutations.Generate(long.Parse(numberString));
//remove any permutations that begin with 0, gets removed in the cast
//and therefore isn't a 0 - n pandigital.
pandigitals.RemoveWhere(p => p.ToString().Length != nDigit + 1);
return(pandigitals);
}
public override long Solve()
{
for (int number = 1490; number < 9999; number++)
{
var perms = Permutations.Generate(number).Where(p => p.ToString().Length == 4);
var permsList = new List <long>();
perms.ToList().ForEach(p => { if (Primes.IsPrime(p))
{
permsList.Add(p);
}
});
if (permsList.Count >= 4)
{
var sequence = FindSequence(permsList);
if (sequence.Count > 0 && !sequence.Contains(1487))
{
return(long.Parse(sequence[0].ToString() + sequence[1].ToString() + sequence[2].ToString()));
}
}
}
throw new Exception("Cannot find sequence....you messed it up");
}
public override void Run()
{
// create a running total
ulong sum = 0;
// create an array to hold the mods
var mods = new[] { 2, 3, 5, 7, 11, 13, 17 };
// create a set of the largest 0-9 pandigital number
var set = "9876543210".ToList();
// permutate the number to get all of the 0-9 pandigital numbers
// that don't begin with '0'
var perm = new Permutations <char>(set);
// go through the numbers
foreach (IList <char> digits in perm)
{
var allHoldProperty = true;
var i = 3;
var m = 0;
while (allHoldProperty && i < digits.Count)
{
var text = string.Concat(digits[i - 2], digits[i - 1], digits[i]);
var num = Convert.ToInt32(text);
allHoldProperty &= (num % mods[m++]) == 0;
++i;
}
if (allHoldProperty)
{
sum += Convert.ToUInt64(string.Concat(digits));
}
}
Console.WriteLine(sum);
}
/// <summary>
/// Get a specific permutation
/// </summary>
/// <param name="list"></param>
/// <param name="index"></param>
/// <returns></returns>
public static string GetPermutation(char[] list, int index)
{
var rawPermutations = new Permutations<char>(list);
var permutations = rawPermutations.Select(chars => string.Join("", chars)).ToList();
if (permutations.Count <= index)
{
throw new ArgumentException("Index is beyond the number of permutations");
}
return permutations[index];
}
public override void Run()
{
var allDigits = "123456789".ToList();
var table = new HashSet <int>();
// a is the number of digits in the multiplicand.
for (var a = 1; a < allDigits.Count; ++a)
{
// create a combinations object to choose the digits for the multiplicand
var multiplicandDigitChooser = new Combinations <char>(allDigits, a);
foreach (var multiplicandDigits in multiplicandDigitChooser)
{
// get the available digits for the multiplier
var availableMultiplierDigits = allDigits.Except(multiplicandDigits).ToList();
// now that we have the multiplicand digits, we need to generate permutations of the digits
var multiplicandNumbers =
new Permutations <char>(multiplicandDigits)
.Select(ch => Convert.ToInt32(string.Join("", ch)))
.ToArray();
// b is the number of digits in the multiplier.
for (var b = 1; b < availableMultiplierDigits.Count; ++b)
{
// create a combinations object to choose the digits for the multiplier
var multiplierDigitChooser = new Combinations <char>(availableMultiplierDigits, b);
foreach (var multiplierDigits in multiplierDigitChooser)
{
// now that we have the multiplier digits, we need to generate permutations of the digits
var multiplierNumbers =
new Permutations <char>(multiplierDigits)
.Select(ch => Convert.ToInt32(string.Join("", ch)))
.ToArray();
// get the available digits for the product, and sort them
var availableProductDigits = string.Join("", availableMultiplierDigits
.Except(multiplierDigits)
.OrderBy(c => c));
// now, we need to multiply the two together and see if they match the available
// product digits
for (var i = 0; i < multiplicandNumbers.Length; ++i)
{
var multiplicand = multiplicandNumbers[i];
for (var j = 0; j < multiplierNumbers.Length; ++j)
{
var multiplier = multiplierNumbers[j];
var product = multiplicand * multiplier;
var text = string.Join("", product.ToString().OrderBy(c => c));
if (text.Equals(availableProductDigits))
{
// the multiplicand/multiplier/product identity can be written as a 1 through 9 pandigital,
// so add the product to the table
table.Add(product);
}
}
}
}
}
}
}
// return the sum of the values in the table
Console.WriteLine(table.Sum());
}