Print non repeating combinations

Question

I have a 6 strings e.g. A, B, C, D, E, F

I want to print them as below in C#, No combination should repeat.

A
A + B
A + C
A + D
A + E
A + F

A + B + C
A + B + D
A + B + E
A + B + F

A + C + D
A + C + E
A + C + F

A + D + E
A + D + F

A + E + F

B + C + D
etc

Can it be done using Linq? any approach is OK for me. Thanks with hope.

Since you already know they're called _combinations_, why not just search for it? Maybe you'll stumble on something like [this](http://codereview.stackexchange.com/questions/51938/get-distinct-combinations-of-numbers) or [this](http://stackoverflow.com/questions/7802822/all-possible-combinations-of-a-list-of-values-in-c-sharp). — Andrei V, May 12 '15 at 14:06

score 0 · Accepted Answer · answered May 12 '15 at 14:18

Interesting task. Try following code:

List<string> list = Enumerable.Range(1, 6).Select(e => ((char)('A' + e - 1)).ToString()).ToList();
List<string> temp = new List<string>();

int count = list.Count;
int total = 1 << list.Count;
for (int i = 0; i < total; i++)
{
    int k = i;
    temp.Clear();
    for (int j = 0; j < count; j++)
    {
        if ((k & 1) == 1)
        {
            temp.Add(list[j]);
        }
        k >>= 1;
    }
    Console.WriteLine(string.Join(" + ", temp.ToArray()));
}

Output:

A
B
A + B
C
A + C
B + C
A + B + C
D
A + D
B + D
A + B + D
C + D
A + C + D
B + C + D
A + B + C + D
E
A + E
B + E
A + B + E
C + E
A + C + E
B + C + E
A + B + C + E
D + E
A + D + E
B + D + E
A + B + D + E
C + D + E
A + C + D + E
B + C + D + E
A + B + C + D + E
F
A + F
B + F
A + B + F
C + F
A + C + F
B + C + F
A + B + C + F
D + F
A + D + F
B + D + F
A + B + D + F
C + D + F
A + C + D + F
B + C + D + F
A + B + C + D + F
E + F
A + E + F
B + E + F
A + B + E + F
C + E + F
A + C + E + F
B + C + E + F
A + B + C + E + F
D + E + F
A + D + E + F
B + D + E + F
A + B + D + E + F
C + D + E + F
A + C + D + E + F
B + C + D + E + F
A + B + C + D + E + F

Print non repeating combinations

1 Answers1