Get combinations of K size based off of a dictionary c#

Question

I have a dictionary like this.

Dictionary<int, string> Diccionario = new Dictionary<int, string>(){
        {1,"124"}  ,  {4,"1457"}  ,  {7,"478"},
        {2,"1235"} ,  {5,"24568"} ,  {8,"05789"},
        {3,"236"}  ,  {6,"3569"}  ,  {9,"698"},
        {0,"08"}   
};

And I'd like to get all combinations for n integer. For example.

for n = 11 - 11, 12, 14, 21, 22, 24, 41, 42, 44.

for n = 24- 11, 14, 15, 17, 21, 24, 25, 27, 31, 34, 35, 37, 51, 54, 55, 57.

for n = 339 - 236, 256, 259...

And so on... But I don't have ANY IDEA how I could iterate through all of those numbers, since the lenght of every number isn't always the same. (1 has three possible combinations, 2 has four; and so on)

Thanks!

Since you guys asked me where does the data come from... It comes from here.

Imagine the PIN is 1273, then it's necessary to create all possible combinations based on the adjacent digit (horizontally and vertically) for example (1 has 2, 3 and the number itself), to make it easier I made the dictionary that can be seen earlier, giving each key its possible value.

Since the answer was closed, I'm not sure what kind of info more I could add, because I can't say too much about the problem. It's like if I had a dictionary of colors, for example:

Dictionary<int, string> Diccionario = new Dictionary<int, string[]>(){
        {1,{"red"}, {"blue"}, {"green"}} , 
        {2,{{"green"}, {"orange"} },
        {3, {{"dark"}}

};

So if I got the number 32 combinations would be: Dark Green or Dark Orange

Not sure If I'm ilustring my point.

Answer 1

After some comments, I think I figured out your problems (there are more then one).

• Diccionario should be a Dictionary<int, int[]>. String is a terrible type to work with. And as you do not seem to use the * and # keys, I see no call for char either.
• Even a dictionary might go overboard. A simple indexed collection could also do it. You should normally only use it if the indexes are non-contiguoius. But for readability this dictionary can work here.
• The input n is also not a single number, but an array of int[]

For input {3, 3, 9} you want all combinations of {2, 3, 6}, {2, 3, 6} and { 6, 8, 9}. It would be possible doing that with 4+ layers of nested loops, but you propably want to look into recursion. This is a inherently recursive operation.

I am at a big loss for naming the arguments and variables, however. That makes writing example code pretty hard.

Answer 2

You are trying to do Cartesian product. This is solved here: Generating all Possible Combinations (all credits to Eric Lippert)

Using that function, the task is really easy:

private static readonly int[][] adjacent = new int[][]
    {
        new int[]{0,8},//0
        new int[]{1,2,4},//1  
        new int[]{1,2,3,5},//2
        new int[]{2,3,6},//3
        new int[]{1,4,5,7},//4  
        new int[]{2,4,5,6,8},//5
        new int[]{3,5,6,9},//6
        new int[]{4,7,8},//7
        new int[]{0,5,7,8,9},//8
        new int[]{6,9,8}//9                
    };

public static IEnumerable<IEnumerable<int>> GetCombinations(int[] input)
{
    if (input.Length == 0) { return new int[0][]; }

    return CartesianProduct(input.Select(n => adjacent[n]));
}

You replace every number in input with the array of adjacent numbers and do a Cartesian product. There is a special case for empty input, the CartesianProduct function returns one empty sequence, which is not the correct result I guess. It should return empty sequence of sequences.