Combinations - kodapor

gistfile1.coffee

flatten = (arrays) ->
  result = []
  arrays.forEach (array) ->
    result = result.concat(array)
  result

combinations = (n, values) ->
  return [[]] if n <= 0
  
  flatten [0 ... values.length].map (x) ->
    head = values[x]
    rest = values.slice(x+1)
    subCombinations = combinations(n-1, rest)
    subCombinations.map (subCombination) -> [head].concat(subCombination)

allCombinations = (n, values) ->
  flatten [1 .. n].map (newN) ->
    combinations(newN, values)




console.log allCombinations(4, [5, 4, 3, 2, 1])