From e49e64ceef4bbf884181432900530eee00e443be Mon Sep 17 00:00:00 2001
From: m5r <mokht@rmi.al>
Date: Wed, 4 Dec 2024 00:16:54 +0100
Subject: [PATCH] day 2 part 2 done naively

---
 lib/day02.ex | 90 +++++++++++++++++++++++-----------------------------
 1 file changed, 39 insertions(+), 51 deletions(-)

diff --git a/lib/day02.ex b/lib/day02.ex
index 4e17588..3431cd6 100644
--- a/lib/day02.ex
+++ b/lib/day02.ex
@@ -1027,78 +1027,66 @@ defmodule AdventOfCode.Day02 do
   end
 
   defp is_ascending_order?(report) do
-    count_out_of_order_ascending(report) == 0
-  end
-
-  defp count_out_of_order_ascending(report) do
     Enum.with_index(report)
-    |> Enum.map(fn {level, index} ->
-      is_last_level = index == length(report) - 1
-
-      case is_last_level do
-        true -> true
-        false -> level < Enum.at(report, index + 1)
+    |> Enum.reduce(true, fn {level, index}, acc ->
+      case index == length(report) - 1 do
+        true -> acc
+        false -> acc and level < Enum.at(report, index + 1)
       end
     end)
-    |> Enum.filter(fn item -> item == false end)
-    |> length()
   end
 
   defp is_descending_order?(report) do
-    count_out_of_order_descending(report) == 0
-  end
-
-  defp count_out_of_order_descending(report) do
     Enum.with_index(report)
-    |> Enum.map(fn {level, index} ->
-      is_last_level = index == length(report) - 1
-
-      case is_last_level do
-        true -> true
-        false -> level > Enum.at(report, index + 1)
+    |> Enum.reduce(true, fn {level, index}, acc ->
+      case index == length(report) - 1 do
+        true -> acc
+        false -> acc and level > Enum.at(report, index + 1)
       end
     end)
-    |> IO.inspect()
-    |> Enum.filter(fn item -> item == false end)
-    |> length()
   end
 
   defp difference_is_within_limits?(report) do
-    count_outside_limits(report) == 0
-  end
-
-  defp count_outside_limits(report) do
     Enum.with_index(report)
-    |> Enum.map(fn {level, index} ->
-      is_last_level = index == length(report) - 1
-
-      case is_last_level do
+    |> Enum.reduce(true, fn {level, index}, acc ->
+      case index == length(report) - 1 do
         true ->
-          true
+          acc
 
         false ->
           difference = abs(level - Enum.at(report, index + 1))
-          difference >= 1 and difference <= 3
+          acc and difference >= 1 and difference <= 3
       end
     end)
-    |> Enum.filter(fn item -> item == false end)
-    |> length()
-  end
-
-  defp count_unsafe(report) do
-    outside_limits = count_outside_limits(report)
-    out_of_order_ascending = count_out_of_order_ascending(report)
-    out_of_order_descending = count_out_of_order_descending(report)
-
-    IO.inspect({outside_limits, out_of_order_ascending, out_of_order_descending})
-
-    outside_limits + out_of_order_ascending + out_of_order_descending
   end
 
   def part2() do
-    parse_reports(@input_test)
-    |> Enum.map(fn report -> count_unsafe(report) end)
-    |> Enum.filter(fn result -> result <= 1 end)
-    |> length()
+    reports = parse_reports(@input)
+    first_round = reports |> Enum.map(fn report -> is_safe?(report) end)
+    safe_results = Enum.filter(first_round, fn result -> result == true end) |> length()
+
+    potentially_safe_results =
+      Enum.map(reports, fn report ->
+        case is_safe?(report) do
+          true ->
+            nil
+
+          false ->
+            Enum.with_index(report)
+            |> Enum.reduce(false, fn {_level, index}, acc ->
+              case acc do
+                true ->
+                  true
+
+                false ->
+                  List.delete_at(report, index) |> is_safe?()
+              end
+            end)
+        end
+      end)
+      |> Enum.filter(fn result -> result == true end)
+      |> length()
+
+    safe_results + potentially_safe_results
   end
 end