You will be given as input a non-empty list of positive integers. For example:
[1,2,2,2,1]
You want to produce a ragged list as output which has this as its "depth map". This list should have the same elements in the same order but each element n should be at the depth equal to its value.
[1,[2,2,2],1]
This is a list where the 1s are at the first level, the 2s are nested in there, the threes would be nested in that etc.
There are multiple outputs that fit this description:
[1,[2],[2],[2],1]
[1,[],[2,[],2,2],1]
[1,[2,2,2],1,[[[]]]]
We want the simplest one, that is the one with the fewest lists total. So in this case
[1,[2,2,2],1]
only has 2 lists whereas all the other examples had more.
Task
Take a depth map and produce the simplest ragged list that it could represent as outlined above.
This is code-golf so the goal is to minimize the size of your source code as scored in bytes.
Test cases
[1] -> [1]
[2] -> [[2]]
[3] -> [[[3]]]
[10] -> [[[[[[[[[[10]]]]]]]]]]
[1,2] -> [1,[2]]
[2,2] -> [[2,2]]
[2,1,2] -> [[2],1,[2]]
[1,2,3,2] -> [1,[2,[3],2]]
[1,2,3,3,3,2,1] -> [1,[2,[3,3,3],2],1]
[1,2,1,2,1,3,3,1] -> [1,[2],1,[2],1,[[3,3]],1]