Sorting an array by corresponding ranges

Question

My purpose is to populate an array from list:

list = [-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 12, 13, 15]

in an order following this:

• Individual integers not followed by its incremented value (by 1) will be added directly to the result array.
• Integers which is followed by its incremented value (by 1) will be added to the range array and this array will then be added to result and will be reset again to be used for the next range.

The correct output should be:

solution(list)
# => [-6, [-3, -2, -1, 0, 1], [3, 4, 5], [7, 8, 9, 10], [12, 13], 15]  

My code and my output is below.

def solution(list)
  result = []
  idx = 0
  loop do
    range = []
    loop do
      if list[idx+1] - list[idx] == 1
        range << list[idx]
        idx += 1
      else
        result << list[idx]
        idx += 1
        break
      end
    end
    result << range
  break if idx == list.size - 1
  end
  result
end 

solution(list)
# => [-6, [], 1, [-3, -2, -1, 0], 5, [3, 4], 10, [7, 8, 9], 13, [12]]

The code is not correct. Can you tell me what I am missing?

Answer 1

You're missing chunk_while.

list.chunk_while{|a, b| a.next == b}.map{|a| a.one? ? a.first : a}
# => [-6, [-3, -2, -1, 0, 1], [3, 4, 5], [7, 8, 9, 10], [12, 13], 15]