joshua.aug
Create all possible teams from a list of players
Say I have a list of players and I want to separate them into two teams of identical size. I want to know what are all the possibilities.
Here is some code that works if I have 16 players and want to know all possible combos of Team 1:
def potential_teams_of_8() do
num_players = 16
last = num_players - 1
# AWLOG the first player is on the team
for i1 <- 0..0,
i2 <- (i1 + 1)..(last - 6),
i3 <- (i2 + 1)..(last - 5),
i4 <- (i3 + 1)..(last - 4),
i5 <- (i4 + 1)..(last - 3),
i6 <- (i5 + 1)..(last - 2),
i7 <- (i6 + 1)..(last - 1),
i8 <- (i7 + 1)..last,
do: [i1, i2, i3, i4, i5, i6, i7, i8]
end
How do I make this function more general such that it can handle any number of players?
It’s slightly different than combinations. Combinations would give double the number of results.
Team1: 0,1,2,3,4,5,6,7
Team2: 8,9,10,11,12,13,14,15
is identical to
Team1: 8,9,10,11,12,13,14,15
Team2: 0,1,2,3,4,5,6,7
So the number of combos is halved.
Marked As Solved
Kabawo
Looking at the library proposed by dimitarvp, you could adapt it something like this for your specific use case:
defmodule Comb do
defp n_comb(0, _list), do: [[]]
defp n_comb(_, []), do: []
defp n_comb(n, [h | t]) do
list = for l <- n_comb(n-1, t), do: [h | l]
list ++ n_comb(n, t)
end
def n_comb(list) do
n = trunc(length(list)/2)
for i <- n_comb(n-1, tl(list)),
do: [hd(list) | i]
end
end
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dimitarvp
If you’re not willing to devise the algorithm then I’d think Combinatorics.n_combinations/2 will serve you fine.
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