!YS-v0

defn main():
  open =:
    reduce _ vec([true] * 100) (1 .. 100):
      fn(doors i):
        loop j i, doors doors:
          if j < 100:
            recur (j + i).++:
              update-in doors [j]: \(doors.$j.!)
            else: doors
  say: -"Open doors after 100 passes:\ " +
        (1 .. 100).map(\(_.--:open && _))
                  .filter(a).join(', ')