is this correct algorithm for part2?
invalid: [[47, 89, 77, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]]
current: [47, 89, 77, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 1 with 77 at index 2"
current: [47, 77, 89, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 47 at index 0 with 74 at index 3"
current: [74, 77, 89, 47, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 2 with 61 at index 4"
current: [74, 77, 61, 47, 89, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 77 at index 1 with 61 at index 2"
current: [74, 61, 77, 47, 89, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 4 with 53 at index 5"
current: [74, 61, 77, 47, 53, 89, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 47 at index 3 with 53 at index 4"
current: [74, 61, 77, 53, 47, 89, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 77 at index 2 with 53 at index 3"
current: [74, 61, 53, 77, 47, 89, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 61 at index 1 with 53 at index 2"
current: [74, 53, 61, 77, 47, 89, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 74 at index 0 with 53 at index 1"
current: [53, 74, 61, 77, 47, 89, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 5 with 82 at index 6"
current: [53, 74, 61, 77, 47, 82, 89, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 61 at index 2 with 82 at index 5"
current: [53, 74, 82, 77, 47, 61, 89, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 74 at index 1 with 82 at index 2"
current: [53, 82, 74, 77, 47, 61, 89, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 61 at index 5 with 38 at index 7"
current: [53, 82, 74, 77, 47, 38, 89, 61, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 47 at index 4 with 38 at index 5"
current: [53, 82, 74, 77, 38, 47, 89, 61, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 77 at index 3 with 38 at index 4"
current: [53, 82, 74, 38, 77, 47, 89, 61, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 82 at index 1 with 38 at index 3"
current: [53, 38, 74, 82, 77, 47, 89, 61, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 74 at index 2 with 73 at index 9"
current: [53, 38, 73, 82, 77, 47, 89, 61, 45, 74, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 45 at index 8 with 15 at index 10"
current: [53, 38, 73, 82, 77, 47, 89, 61, 15, 74, 45, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 6 with 15 at index 8"
current: [53, 38, 73, 82, 77, 47, 15, 61, 89, 74, 45, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 77 at index 4 with 15 at index 6"
current: [53, 38, 73, 82, 15, 47, 77, 61, 89, 74, 45, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 45 at index 10 with 76 at index 11"
current: [53, 38, 73, 82, 15, 47, 77, 61, 89, 74, 76, 45, 41, 24, 56, 55, 67, 68, 95]
"replace 82 at index 3 with 76 at index 10"
current: [53, 38, 73, 76, 15, 47, 77, 61, 89, 74, 82, 45, 41, 24, 56, 55, 67, 68, 95]
"replace 38 at index 1 with 76 at index 3"
current: [53, 76, 73, 38, 15, 47, 77, 61, 89, 74, 82, 45, 41, 24, 56, 55, 67, 68, 95]
"replace 47 at index 5 with 41 at index 12"
current: [53, 76, 73, 38, 15, 41, 77, 61, 89, 74, 82, 45, 47, 24, 56, 55, 67, 68, 95]
"replace 15 at index 4 with 41 at index 5"
current: [53, 76, 73, 38, 41, 15, 77, 61, 89, 74, 82, 45, 47, 24, 56, 55, 67, 68, 95]
"replace 15 at index 5 with 24 at index 13"
current: [53, 76, 73, 38, 41, 24, 77, 61, 89, 74, 82, 45, 47, 15, 56, 55, 67, 68, 95]
"replace 15 at index 13 with 55 at index 15"
current: [53, 76, 73, 38, 41, 24, 77, 61, 89, 74, 82, 45, 47, 55, 56, 15, 67, 68, 95]
"replace 89 at index 8 with 55 at index 13"
current: [53, 76, 73, 38, 41, 24, 77, 61, 55, 74, 82, 45, 47, 89, 56, 15, 67, 68, 95]
"replace 77 at index 6 with 55 at index 8"
current: [53, 76, 73, 38, 41, 24, 55, 61, 77, 74, 82, 45, 47, 89, 56, 15, 67, 68, 95]
"replace 24 at index 5 with 55 at index 6"
current: [53, 76, 73, 38, 41, 55, 24, 61, 77, 74, 82, 45, 47, 89, 56, 15, 67, 68, 95]
"replace 73 at index 2 with 67 at index 16"
current: [53, 76, 67, 38, 41, 55, 24, 61, 77, 74, 82, 45, 47, 89, 56, 15, 73, 68, 95]
"replace 45 at index 11 with 68 at index 17"
current: [53, 76, 67, 38, 41, 55, 24, 61, 77, 74, 82, 68, 47, 89, 56, 15, 73, 45, 95]
"replace 24 at index 6 with 68 at index 11"
current: [53, 76, 67, 38, 41, 55, 68, 61, 77, 74, 82, 24, 47, 89, 56, 15, 73, 45, 95]
"replace 55 at index 5 with 68 at index 6"
current: [53, 76, 67, 38, 41, 68, 55, 61, 77, 74, 82, 24, 47, 89, 56, 15, 73, 45, 95]
"replace 15 at index 15 with 95 at index 18"
current: [53, 76, 67, 38, 41, 68, 55, 61, 77, 74, 82, 24, 47, 89, 56, 95, 73, 45, 15]
"replace 56 at index 14 with 95 at index 15"
current: [53, 76, 67, 38, 41, 68, 55, 61, 77, 74, 82, 24, 47, 89, 95, 56, 73, 45, 15]
"replace 77 at index 8 with 95 at index 14"
fixed: [[53, 76, 67, 38, 41, 68, 55, 61, 95, 74, 82, 24, 47, 89, 77, 56, 73, 45, 15]]
If i a find a rule for a number in an update, where the update number should be before the the second number in the rule, i swap them with two simple replace_at
IO.inspect(acc_, label: "current", charlists: :as_lists, limit: :infinity)
IO.inspect("replace #{b} at index #{b_index} with #{next} at index #{new_next_id}")
acc_ |> List.replace_at(new_next_id, b) |> List.replace_at(b_index, next)
this part isnt actually rocket science … but i wonder if its correct .. well hard to read so its more like is the assumptions correct
i have looked at some of the rules manually for this example, and it seems to checkout
for ex the first one is a good example for all the others, and it represents what all the others do
invalid: [[47, 89, 77, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]]
current: [47, 89, 77, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
"replace 89 at index 1 with 77 at index 2"
current: [47, 77, 89, 74, 61, 53, 82, 38, 45, 73, 15, 76, 41, 24, 56, 55, 67, 68, 95]
here 89 swaps place with 77.
Is it correct assumption that the rules is always left to right oriented maybe?
The full “documented” algorithm in its full glory:
defp fix_invalid_update(update, rules) do
update
# reduce with update itself as accumulator
|> Enum.reduce(update, fn next, acc ->
rules
# get alll the rules for the number "next",
# assuming i should only get rules where number "next" is the first number in the rule
|> Enum.filter(&(&1 |> Tuple.to_list() |> hd() == next))
# reduce the rules with the current acumulator as accumulator (the update)
|> Enum.reduce(acc, fn {_, b}, acc_ ->
b_index = acc_ |> Enum.find_index(&(&1 == b))
# find new position for next, since it can have changed since last iteration
new_next_id = acc_ |> Enum.find_index(&(&1 == next))
if b_index == nil do
acc_
else
if b_index < new_next_id do
IO.inspect(acc_, label: "current", charlists: :as_lists, limit: :infinity)
IO.inspect("replace #{b} at index #{b_index} with #{next} at index #{new_next_id}")
acc_ |> List.replace_at(new_next_id, b) |> List.replace_at(b_index, next)
else
acc_
end
end
end)
end)
end
havent read the others solutions yet. If i cant make it work myself its not worth the cheat 
This took me longer than I wanted, but I was out today. I’m just glad to have it done before the next one.