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Tidy up day 5 a bit

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Adam Millerchip 2023-12-06 21:57:43 +09:00
parent 684438a5a1
commit f180c206ac
1 changed files with 10 additions and 13 deletions
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23
2023/day5.exs
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@ -24,8 +24,8 @@ defmodule Day5 do
maps
|> Enum.reduce(seed_ranges, &process_ranges/2)
|> Enum.min_by(& &1.first)
|> then(& &1.first)
|> Enum.map(& &1.first)
|> Enum.min()
end
def process_ranges(_map_ranges, []), do: []
@ -35,23 +35,20 @@ defmodule Day5 do
Enum.find(map_ranges, fn {source, _offset} -> not Range.disjoint?(source, item_range) end)
case overlap do
nil ->
[item_range | process_ranges(map_ranges, rest)]
{source, offset} ->
to_shift = max(source.first, item_range.first)..min(source.last, item_range.last)
# ugh. Tidy this up
remainders =
List.flatten([
if(item_range.first < source.first,
do: [item_range.first..(source.first - 1)],
else: []
),
if(item_range.last > source.last, do: [(source.last + 1)..item_range.last], else: [])
])
[
if(item_range.first < source.first, do: item_range.first..(source.first - 1)),
if(item_range.last > source.last, do: (source.last + 1)..item_range.last)
]
|> Enum.reject(&is_nil/1)
[Range.shift(to_shift, offset) | process_ranges(map_ranges, remainders ++ rest)]
nil ->
[item_range | process_ranges(map_ranges, rest)]
end
end