/// <summary> Creates one CombinationWithGaps out of the specified ones. </summary>
public static CombinationWithGaps <T> Combine(IEnumerable <CombinationWithGaps <T> > combinations)
{
Contract.Requires(combinations != null);
Contract.LazilyRequires(ref combinations, NotNull);
Contract.Requires(combinations.SelectMany(combi => combi.AllIntervalsIn()).ToSortedList(IntervalExtensions.Compare).AreDisjoint());
return(new CombinationWithGaps <T>(combinations.SelectMany(combi => combi.Combination).ToReadOnlyList(),
combinations.SelectMany(combi => combi.Gaps).ToList()));
}
private static IEnumerable <T[]> AllCombinations <T>(IEnumerable <int> counts, Func <int, int, T> select)
{
Contract.Requires(counts != null);
Contract.LazilyRequires(ref counts, count => count >= 0);
Contract.Requires(select != null);
var result = EnumerableExtensions.Range(counts.ToList())
.Select(elementIndices => elementIndices.Map(select));
EnsureSingleEnumerationDEBUG(ref result);
return(result);
}