# Collatz Conjecture in Standard ML

#### Calculate the number of steps to reach 1 using the Collatz conjecture

1 | ```
exercism fetch sml collatz-conjecture
``` |

# Collatz Conjecture

The Collatz Conjecture or 3x+1 problem can be summarized as follows:

Take any positive integer n. If n is even, divide n by 2 to get n / 2. If n is odd, multiply n by 3 and add 1 to get 3n + 1. Repeat the process indefinitely. The conjecture states that no matter which number you start with, you will always reach 1 eventually.

Given a number n, return the number of steps required to reach 1.

## Examples

Starting with n = 12, the steps would be as follows:

- 12
- 6
- 3
- 10
- 5
- 16
- 8
- 4
- 2
- 1

Resulting in 9 steps. So for input n = 12, the return value would be 9.

## Loading your exercise implementation in PolyML

1 |
```
$ poly --use {exercise}.sml
``` |

Or:

**Note:** You have to replace {exercise}.

## Running the tests

1 |
```
$ poly -q --use test.sml
``` |

## Feedback, Issues, Pull Requests

The exercism/sml repository on GitHub is the home for all of the Standard ML exercises.

If you have feedback about an exercise, or want to help implementing a new one, head over there and create an issue. We'll do our best to help you!

## Source

An unsolved problem in mathematics named after mathematician Lothar Collatz https://en.wikipedia.org/wiki/3x_%2B_1_problem

## Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.