C# : creating unique one-dimensional arrays from two-dimensional arrays-CodePudding

input Data

1 -> [2] 
2 -> [3, 5, 7, 9]
3 -> [4]
4 -> [5]
5 -> [6]
6 -> [7, 9]
7 -> [8]
8 -> [9]
tree child

how can i get output like below using data above a few for loop checks but i couldn't. I want something like combination but infinite

Out data

1,2,3,4,5,6,7,8,9

1,2,3,4,5,6,9

1,2,5,6,7,8,9

1,2,5,6,9

1,2,7,8,9

1,2,9

CodePudding user response：

Assuming your input tree isn't too large, you could use recursion to achieve what you want to do.

Let's say your input data is populated in a Dictionary, as follows:

var input = new Dictionary<int, int[]>
{
    [1] = new[] { 2 },
    [2] = new[] { 3, 5, 7, 9 },
    [3] = new[] { 4 },
    [4] = new[] { 5 },
    [5] = new[] { 6 },
    [6] = new[] { 7, 9 },
    [7] = new[] { 8 },
    [8] = new[] { 9 }
};

var output = input.GetPossibleRanges();

You could then "build" all possible tree branches recursively, using extension methods such as:

public static IEnumerable<List<int>> GetPossibleRanges(this Dictionary<int, int[]> dict)
{
    var ranges = new List<int> { dict.Keys.Min() }.BuildRanges(dict);

    return ranges;
}

public static IEnumerable<List<int>> BuildRanges(this List<int> range, Dictionary<int, int[]> dict)
{
    if (dict.TryGetValue(range.Last(), out int[] nextLevel))
    {
        foreach (var child in nextLevel)
        {
            foreach (var grownRange in range.Append(child).ToList().BuildRanges(dict))
            {
                yield return grownRange;
            }
        }
    }
    else
    {
        yield return range;
    }
}

Given the provided input, the resulting output is then:

foreach (var entry in output)
{
    Console.WriteLine(string.Join(",", entry));
}

1,2,3,4,5,6,7,8,9
1,2,3,4,5,6,9
1,2,5,6,7,8,9
1,2,5,6,9
1,2,7,8,9
1,2,9

CodePudding user response：

public static IEnumerable<List> GetPossibleRanges(this Dictionary<int, int[]> dict) { var ranges = new List { dict.Keys.Min() }.BuildRanges(dict);

        return ranges;
    }

    public static IEnumerable<List<int>> BuildRanges(this List<int> range, Dictionary<int, int[]> dict) {
        if (dict.TryGetValue(range.Last(), out int[] nextLevel)) {
            foreach (var child in nextLevel) {
                range.Add(child);

                foreach (var grownRange in range.ToList().BuildRanges(dict)) {
                    yield return grownRange;
                }
            }
        } else {
            yield return range;
        }
    }

1,2,3,4,5,6,7,8,9 1,2,3,4,5,6,7,9 1,2,3,5,6,7,8,9 1,2,3,5,6,7,9 1,2,3,5,7,8,9 1,2,3,5,7,9

range.Append(child).ToList().BuildRanges(dict)

Append Error