Split value in 24 randomly sized parts using C#

Question

I have a value, say 20010. I want to randomly divide this value over 24 hours. So basically split the value into a 24 slot big array where all slots are randomly big.

What could be a good way solving this using C#?

Answer 1

Draw 23 (not 24) numbers at random, (without duplicates), in the range 1 to 20009. Add 0 and 20010 the list and order these numbers, the difference between each two consecutive number gives you one slot value.

An online approach is also possible by drawing one value at a time and subtracting it from the "pot", drawing anew when the number is bigger than the amount left. This approach however may lead to a greater deviation of the size of the slots.

Answer 2

Here's a functional solution using mjv's algorithm:

static int[] GetSlots(int slots, int max)
{
    return new Random().Values(1, max)
                       .Take(slots - 1)
                       .Append(0, max)
                       .OrderBy(i => i)
                       .Pairwise((x, y) => y - x)
                       .ToArray();
}

public static IEnumerable<int> Values(this Random random, int minValue, int maxValue)
{
    while (true)
        yield return random.Next(minValue, maxValue);
}

public static IEnumerable<TResult> Pairwise<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TSource, TResult> resultSelector)
{
    TSource previous = default(TSource);

    using (var it = source.GetEnumerator())
    {
        if (it.MoveNext())
            previous = it.Current;

        while (it.MoveNext())
            yield return resultSelector(previous, previous = it.Current);
    }
}

public static IEnumerable<T> Append<T>(this IEnumerable<T> source, params T[] args)
{
    return source.Concat(args);
}