# Pov

Reparent a graph on a selected node.

# Tree Reparenting

This exercise is all about re-orientating a graph to see things from a different
point of view. For example family trees are usually presented from the
ancestor's perspective:

```
    +------0------+
    |      |      |
  +-1-+  +-2-+  +-3-+
  |   |  |   |  |   |
  4   5  6   7  8   9
```

But the same information can be presented from the perspective of any other node
in the graph, by pulling it up to the root and dragging its relationships along
with it. So the same graph from 6's perspective would look like:

```
        6
        |
  +-----2-----+
  |           |
  7     +-----0-----+
        |           |
      +-1-+       +-3-+
      |   |       |   |
      4   5       8   9
```

This lets us more simply describe the paths between two nodes. So for example
the path from 6-9 (which in the first graph goes up to the root and then down to
a different leaf node) can be seen to follow the path 6-2-0-3-9

This exercise involves taking an input graph and re-orientating it from the point
of view of one of the nodes.


## Getting Started

For installation and learning resources, refer to the
[exercism help page](http://exercism.io/languages/haskell).

## Running the tests

To run the test suite, execute the following command:

```bash
stack test
```

#### If you get an error message like this...

```
No .cabal file found in directory
```

You are probably running an old stack version and need
to upgrade it.

#### Otherwise, if you get an error message like this...

```
No compiler found, expected minor version match with...
Try running "stack setup" to install the correct GHC...
```

Just do as it says and it will download and install
the correct compiler version:

```bash
stack setup
```

## Running *GHCi*

If you want to play with your solution in GHCi, just run the command:

```bash
stack ghci
```

## Feedback, Issues, Pull Requests

The [exercism/haskell](https://github.com/exercism/haskell) repository on
GitHub is the home for all of the Haskell 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

Adaptation of exercise from 4clojure [https://www.4clojure.com/](https://www.4clojure.com/)

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