Generating Permutations using LINQ

Question

I have a set of products that must be scheduled. There are P products each indexed from 1 to P. Each product can be scheduled into a time period 0 to T. I need to construct

Answer 1

The output from the answer of Mr Lippert can be seen as all the possible distributions of elements among 0 and 2 in 4 slots.
For instance
0 3 1
reads as "no 0, three 1 and one 2"
This is nowhere near as elegant as the answer of Mr Lippert, but at least not less efficient

public static void Main()
{
  var distributions = Distributions(4, 3);
  PrintSequences(distributions);
}

/// 

/// Entry point for the other recursive overload
/// 
/// Number of elements in the output
/// Number of distinct values elements can take
/// 
static List Distributions(int length, int range)
{
  var distribution = new int[range];
  var distributions = new List();
  Distributions(0, length, distribution, 0, distributions);
  distributions.Reverse();
  return distributions;
}

/// 

/// Recursive methode. Not to be called directly, only from other overload
/// 
/// Value of the (possibly) last added element
/// Number of elements in the output
/// Distribution among element distinct values
/// Exit condition of the recursion. Incremented if element added from parent call
/// All possible distributions
static void Distributions(int index,
                          int length,
                          int[] distribution,
                          int sum,
                          List distributions)
{
  //Uncomment for exactness check
  //System.Diagnostics.Debug.Assert(distribution.Sum() == sum);
  if (sum == length)
  {
    distributions.Add(distribution.Reverse().ToArray());

    for (; index < distribution.Length; index++)
    {
      sum -= distribution[index];
      distribution[index] = 0;
    }
    return;
  }
  if (index < distribution.Length)
  {
    Distributions(index + 1, length, distribution, sum, distributions);
    distribution[index]++;
    Distributions(index, length, distribution, ++sum, distributions);
  }
}

static void PrintSequences(List distributions)
{
  for (int i = 0; i < distributions.Count; i++)
  {
    for (int j = distributions[i].Length - 1; j >= 0; j--)
      for (int k = 0; k < distributions[i][j]; k++)
        Console.Write("{0:D1} ", distributions[i].Length - 1 - j);
    Console.WriteLine();
  }
}