> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/1/100_doors.md).

# 100 doors

*Unoptimized*

```ruby
var doors = []

{ |pass|
    { |i|
        if (pass `divides` i) {
            doors[i] := false -> not!
        }
    } << 1..100
} << 1..100

{ |i|
    say ("Door %3d is %s" % (i, doors[i] ? 'open' : 'closed'))
} << 1..100
```

*Optimized*

```ruby
{ |i|
    "Door %3d is %s\n".printf(i, <closed open>[i.is_sqr])
} << 1..100
```