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Add flatten-array exercise (#189)
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BNAndras authored Nov 10, 2023
1 parent 170a0e1 commit 39d859d
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8 changes: 8 additions & 0 deletions config.json
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Expand Up @@ -98,6 +98,14 @@
"transforming"
]
},
{
"slug": "flatten-array",
"name": "Flatten Array",
"uuid": "091cf652-212f-44a6-8187-1a3acdb922e3",
"practices": [],
"prerequisites": [],
"difficulty": 2
},
{
"slug": "hello-world",
"name": "Hello World",
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11 changes: 11 additions & 0 deletions exercises/practice/flatten-array/.docs/instructions.md
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# Instructions

Take a nested list and return a single flattened list with all values except nil/null.

The challenge is to write a function that accepts an arbitrarily-deep nested list-like structure and returns a flattened structure without any nil/null values.

For example:

input: [1,[2,3,null,4],[null],5]

output: [1,2,3,4,5]
19 changes: 19 additions & 0 deletions exercises/practice/flatten-array/.meta/config.json
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{
"authors": [
"BNAndras"
],
"files": {
"solution": [
"flatten_array.vim"
],
"test": [
"flatten_array.vader"
],
"example": [
".meta/example.vim"
]
},
"blurb": "Take a nested list and return a single list with all values except nil/null.",
"source": "Interview Question",
"source_url": "https://reference.wolfram.com/language/ref/Flatten.html"
}
12 changes: 12 additions & 0 deletions exercises/practice/flatten-array/.meta/example.vim
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function! Flatten(array) abort
let l:results = []
for l:elem in a:array
if type(l:elem) == v:t_list
call extend(l:results, Flatten(l:elem))
elseif l:elem isnot v:null
call add(l:results, l:elem)
endif
endfor

return results
endfunction
43 changes: 43 additions & 0 deletions exercises/practice/flatten-array/.meta/tests.toml
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# This is an auto-generated file.
#
# Regenerating this file via `configlet sync` will:
# - Recreate every `description` key/value pair
# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
# - Preserve any other key/value pair
#
# As user-added comments (using the # character) will be removed when this file
# is regenerated, comments can be added via a `comment` key.

[8c71dabd-da60-422d-a290-4a571471fb14]
description = "empty"

[d268b919-963c-442d-9f07-82b93f1b518c]
description = "no nesting"

[3f15bede-c856-479e-bb71-1684b20c6a30]
description = "flattens a nested array"

[c84440cc-bb3a-48a6-862c-94cf23f2815d]
description = "flattens array with just integers present"

[d3d99d39-6be5-44f5-a31d-6037d92ba34f]
description = "5 level nesting"

[d572bdba-c127-43ed-bdcd-6222ac83d9f7]
description = "6 level nesting"

[0705a8e5-dc86-4cec-8909-150c5e54fa9c]
description = "null values are omitted from the final result"

[c6cf26de-8ccd-4410-84bd-b9efd88fd2bc]
description = "consecutive null values at the front of the list are omitted from the final result"

[382c5242-587e-4577-b8ce-a5fb51e385a1]
description = "consecutive null values in the middle of the list are omitted from the final result"

[ef1d4790-1b1e-4939-a179-51ace0829dbd]
description = "6 level nest list with null values"

[85721643-705a-4150-93ab-7ae398e2942d]
description = "all values in nested list are null"
55 changes: 55 additions & 0 deletions exercises/practice/flatten-array/flatten_array.vader
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Execute (empty):
let g:array = []
let g:expected = []
AssertEqual g:expected, Flatten(g:array)

Execute (no nesting):
let g:array = [0, 1, 2]
let g:expected = [0, 1, 2]
AssertEqual g:expected, Flatten(g:array)

Execute (flattens a nested array):
let g:array = [[[]]]
let g:expected = []
AssertEqual g:expected, Flatten(g:array)

Execute (flattens array with just integers present):
let g:array = [1, [2, 3, 4, 5, 6, 7], 8]
let g:expected = [1, 2, 3, 4, 5, 6, 7, 8]
AssertEqual g:expected, Flatten(g:array)

Execute (5 level nesting):
let g:array = [0, 2, [[2, 3], 8, 100, 4, [[[50]]]], -2]
let g:expected = [0, 2, 2, 3, 8, 100, 4, 50, -2]
AssertEqual g:expected, Flatten(g:array)

Execute (6 level nesting):
let g:array = [1, [2, [[3]], [4, [[5]]], 6, 7], 8]
let g:expected = [1, 2, 3, 4, 5, 6, 7, 8]
AssertEqual g:expected, Flatten(g:array)

Execute (null values are omitted from the final result):
let g:array = [1, 2, v:null]
let g:expected = [1, 2]
AssertEqual g:expected, Flatten(g:array)

Execute (consecutive null values at the front of the list are omitted from the final result):
let g:array = [v:null, v:null, 3]
let g:expected = [3]
AssertEqual g:expected, Flatten(g:array)

Execute (consecutive null values in the middle of the list are omitted from the final result):
let g:array = [1, v:null, v:null, 4]
let g:expected = [1, 4]
AssertEqual g:expected, Flatten(g:array)

Execute (6 level nest list with null values):
let g:array = [0, 2, [[2, 3], 8, [[100]], v:null, [[v:null]]], -2]
let g:expected = [0, 2, 2, 3, 8, 100, -2]
AssertEqual g:expected, Flatten(g:array)

Execute (all values in nested list are null):
let g:array = [v:null, [[[v:null]]], v:null, v:null, [[v:null, v:null], v:null], v:null]
let g:expected = []
AssertEqual g:expected, Flatten(g:array)
15 changes: 15 additions & 0 deletions exercises/practice/flatten-array/flatten_array.vim
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"
" Flattens an arbitrarily-deep nested array, removing v:null values.
"
" Examples:
"
" :echo Flatten([])
" []
" :echo Flatten([0, 1, 2])
" [0, 1, 2]
" :echo Flatten([0, 1, [2, 3, v:null]])
" [0, 1, 2, 3]
"
function! Flatten(array) abort
" your implemention goes here
endfunction

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