# Tree random element

**URL:** <https://forum.elixirforum.com/t/tree-random-element/34553>\
**Category:** Coding Challenges\
**Tags:** coding-challenge, trees, random\
**Created:** [September 24, 2020, 11:44am UTC](https://forum.elixirforum.com/t/tree-random-element/34553 "2020-09-24T11:44:11Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![BorjaEst](https://forum.elixirforum.com/user_avatar/forum.elixirforum.com/borjaest/32/19583_2.png) [@BorjaEst](https://forum.elixirforum.com/u/BorjaEst)\
**Post date:** [September 26, 2020, 2:49pm UTC](https://forum.elixirforum.com/t/tree-random-element/34553/4 "2020-09-26T14:49:03Z")

</div>

So after thinking about it, my solution would be something like this:

```elixir
iex(1)> tree = :gb_tree.example() #Any f that returns a tree
{3, {:a, 1, nil, {:b, 2, nil, {:c, 3, nil, nil}}}}
iex(2)> n = :rand.uniform(:gb_trees.size(tree))
2
iex(11)> iter = :gb_trees.iterator(tree) 
[{:a, 1, nil, {:b, 2, nil, {:c, 3, nil, nil}}}]
iex(14)> {k,v,_}=Enum.reduce(1..n, {:nil,:nil,:gb_trees.iterator(tree)}, fn _, {_,_,i} -> :gb_trees.next(i) end)
{:b, 2, [{:c, 3, nil, nil}]}

```

However I am thinking, now gb\_trees are not used any longer as we do have maps.

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