Add moduledoc tags to 2020

Author: code-shoily

lib/2020/day_01.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day01 do
   @moduledoc """
   --- Day 1: Report Repair ---
   Problem Link: https://adventofcode.com/2020/day/1
+  Difficulty: xs
+  Tags: set arithmetic
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_02.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day02 do
   @moduledoc """
   --- Day 2: Password Philosophy ---
   Problem Link: https://adventofcode.com/2020/day/2
+  Difficulty: xs
+  Tags: regex string
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_03.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day03 do
   @moduledoc """
   --- Day 3: Toboggan Trajectory ---
   Problem Link: https://adventofcode.com/2020/day/3
+  Difficulty: xs
+  Tags: grid walk
   """
   alias AdventOfCode.Algorithms.Grid
   alias AdventOfCode.Helpers.{InputReader, Transformers}

lib/2020/day_04.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day04 do
   @moduledoc """
   --- Day 4: Passport Processing ---
   Problem Link: https://adventofcode.com/2020/day/4
+  Difficulty: s
+  Tags: regex validation parse-heavy
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_05.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day05 do
   @moduledoc """
   --- Day 5: Binary Boarding ---
   Problem Link: https://adventofcode.com/2020/day/5
+  Difficulty: xs
+  Tags: binary-space partitioning walk
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_06.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day06 do
   @moduledoc """
   --- Day 6: Custom Customs ---
   Problem Link: https://adventofcode.com/2020/day/6
+  Difficulty: xs
+  Tags: set count
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_07.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day07 do
   @moduledoc """
   --- Day 7: Handy Haversacks ---
   Problem Link: https://adventofcode.com/2020/day/7
+  Difficulty: s
+  Tags: graph-traversal digraph recursion
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_08.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day08 do
   @moduledoc """
   --- Day 8: Handheld Halting ---
   Problem Link: https://adventofcode.com/2020/day/8
+  Difficulty: s
+  Tags: emulation recursion
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_09.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day09 do
   @moduledoc """
   --- Day 9: Encoding Error ---
   Problem Link: https://adventofcode.com/2020/day/9
+  Difficulty: s
+  Tags: sliding-window set
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}
 

lib/2020/day_10.ex

@@ -2,6 +2,8 @@ defmodule AdventOfCode.Y2020.Day10 do
   @moduledoc """
   --- Day 10: Adapter Array ---
   Problem Link: https://adventofcode.com/2020/day/10
+  Difficulty: s
+  Tags: memoization dynamic-programming sort
   """
   alias AdventOfCode.Helpers.{InputReader, Transformers}