Post History

# [Ruby], 33 bytes
Recursive lambda solution.

```ruby
c=->n{n<2?0:1+c[n%2<1?n/2:n*3+1]}

c=->n{                          }  # c = lambda taking `n`
      n<2? :                       # if n < 2...
          0                        # return 0...
            1+c[               ]   # else return 1 + collatz count for...
                n%2<1?   :         # if n is even... 
                      n/2          # n / 2...
                          n*3+1    # else 3n + 1
```

[Try it online!][TIO-kto1bee5]

[Ruby]: https://www.ruby-lang.org/
[TIO-kto1bee5]: https://tio.run/##KypNqvz/P9lW1y6vOs/GyN7AylA7OTpP1cjG0D5P38gqT8tY2zC29n9BaUmxgoahnp6hgaZebmJBdU1mTXJ0JlAGAA "Ruby – Try It Online"