Day 2 part 1

2022/src/days/day_2.gleam

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+import gleam/int
+import gleam/list
+import gleam/string
+
+type Hand {
+  Rock
+  Paper
+  Scissors
+}
+
+type Game =
+  #(Hand, Hand)
+
+pub fn pt_1(input: String) -> Int {
+  string.split(input, on: "\n")
+  |> list.map(parse_line)
+  |> list.map(score_game)
+  |> int.sum
+}
+
+pub fn pt_2(_input: String) -> Int {
+  todo
+}
+
+fn parse_line(line: String) -> Game {
+  assert [a, b] = string.split(line, on: " ")
+  #(to_hand(a), to_hand(b))
+}
+
+fn to_hand(raw: String) -> Hand {
+  case raw {
+    "A" -> Rock
+    "B" -> Paper
+    "C" -> Scissors
+    "X" -> Rock
+    "Y" -> Paper
+    "Z" -> Scissors
+  }
+}
+
+fn score_game(game: Game) -> Int {
+  let score = case game {
+    // (them, me)
+    #(Rock, Paper) -> 6
+    #(Rock, Scissors) -> 0
+    #(Paper, Rock) -> 0
+    #(Paper, Scissors) -> 6
+    #(Scissors, Rock) -> 6
+    #(Scissors, Paper) -> 0
+    #(Rock, Rock) -> 3
+    #(Paper, Paper) -> 3
+    #(Scissors, Scissors) -> 3
+  }
+  score + score_hand(game.1)
+}
+
+fn score_hand(hand: Hand) -> Int {
+  case hand {
+    Rock -> 1
+    Paper -> 2
+    Scissors -> 3
+  }
+}