100 doors

# title: 100 doors
# source: https://rosettacode.org/wiki/100_doors
# category: Rosetta Code
# difficulty: Intro
# summary: Toggle one hundred doors and return the open door numbers.
# tags: popular, loops, arrays, math

def open_doors(limit)
  doors = []
  for _ in 1..limit
    doors = doors.push(false)
  end

  pass = 1
  while pass <= limit
    door = pass
    while door <= limit
      doors[door - 1] = !doors[door - 1]
      door = door + pass
    end
    pass = pass + 1
  end

  open = []
  for door in 1..limit
    if doors[door - 1]
      open = open.push(door)
    end
  end
  open
end

def run
  open_doors(100)
end