static public long Choose(int n, int k, bool isSorted, bool isUnique)
{
long result = 1;
if (!isSorted && !isUnique)
{
for (int i = 0; i < k; i++)
{
result *= n;
}
}
if (!isSorted && isUnique)
{
result = Combinatorial.C(n, k) * Combinatorial.Factorial(k);
}
if (isSorted && isUnique)
{
result = Combinatorial.C(n, k);
}
if (isSorted && !isUnique)
{
result = Combinatorial.C(n + k - 1, k);
}
return(result);
}
public long count(string n)
{
long result = 0;
int[] digits = new int[10];
for (int i = 0; i < n.Length; i++)
{
digits[n[i] - '0']++;
}
while (n != "")
{
for (int i = 0; i < n[0] - '0'; i++)
{
if (digits[i] > 0)
{
int k = n.Length - 1;
long x = 1;
digits[i]--;
for (int j = 0; j < 10; j++)
{
x *= Combinatorial.C(k, digits[j]);
k -= digits[j];
}
digits[i]++;
result += x;
}
}
digits[n[0] - '0']--;
n = n.Substring(1);
}
return(result);
}
/// <summary>
/// Register as /value1/1/value2/2
/// </summary>
public static void RegisterUrlNamedParameters(this RouteCollection routes,
string urlPrefix, string controller, string action,
RoutingParameter[] parameters)
{
foreach (var parameterCombination in
Combinatorial.GetAllSubset(parameters.Length))
{
var url = urlPrefix;
var routeValues = new RouteValueDictionary
{
{ "controller", controller },
{ "action", action }
};
foreach (var i in parameterCombination)
{
var parameter = parameters[i];
url += string.Format("/{0}/{{{1}}}",
parameter.NameInUrl,
parameter.NameInAction);
}
foreach (var parameter in parameters)
{
routeValues.Add(parameter.NameInAction, parameter.DefaultValue);
}
routes.Add(Guid.NewGuid().ToString(), new Route(url,
routeValues, new MvcRouteHandler()));
}
}
public void ABxB()
{
var ab_b = AB * B;
var expectedTypes = new[] { A.ItemType(), B.ItemType(), B.ItemType() };
Assert.That(ab_b, Is.EqualTo(Combinatorial.Of(A, B, B)));
Assert.That(ab_b.GetType().GetGenericArguments(), Is.EquivalentTo(expectedTypes));
}
void TestPermutations(int n, string[] expected)
{
List <string> valueList = new List <string>(16);
Combinatorial.Permutations(n, x => {
string s = string.Join(string.Empty, x);
valueList.Add(s);
});
CollectionAssert.AreEqual(expected, valueList);
}
public void ABxDecimal()
{
var decimals = new List <decimal> {
1, 2, 3
};
var ab_dec = AB.Multiply(decimals);
var expectedTypes = new[] { A.ItemType(), B.ItemType(), decimals.ItemType() };
Assert.That(ab_dec, Is.EqualTo(Combinatorial.Of(A, B, decimals)));
Assert.That(ab_dec.GetType().GetGenericArguments(), Is.EquivalentTo(expectedTypes));
}
protected override void Combinations(IList <int> list, int k, Action <int[]> action)
{
Combinatorial.Combinations(list, k, action);
}
public void PermutationsGuardCase3Test()
{
Combinatorial.Permutations(1, null);
}
public void PermutationsGuardCase2Test()
{
Combinatorial.Permutations(-1, x => { });
}