# Dominoes

Make a chain of dominoes.

Compute a way to order a given set of dominoes in such a way that they form a
correct domino chain (the dots on one half of a stone match the dots on the
neighbouring half of an adjacent stone) and that dots on the halfs of the stones
which don't have a neighbour (the first and last stone) match each other.

For example given the stones `21`, `23` and `13` you should compute something
like `12 23 31` or `32 21 13` or `13 32 21` etc, where the first and last numbers are the same.

For stones 12, 41 and 23 the resulting chain is not valid: 41 12 23's first and last numbers are not the same. 4 != 3

Some test cases may use duplicate stones in a chain solution, assume that multiple Domino sets are being used.


## Getting Started
For installation and learning resources, refer to the
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## Installation
To work on the exercises, you will need `Opam` and `Core`. Consult [opam](https://opam.ocaml.org) website for instructions on how to install `opam` for your OS. Once `opam` is installed open a terminal window and run the following command to install core:

```bash
opam install core
```

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```bash
opam install ounit
```

## Running Tests
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```bash
make
```

## Interactive Shell
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```bash
opam install utop
```
Consult [utop](https://github.com/diml/utop/blob/master/README.md) for more detail.

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## Submitting Incomplete Solutions
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