Day 4

day_02/solve.nim

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+import std/[strutils, tables]
+
+type Shape {.pure.} = enum
+  Rock = 1,
+  Paper = 2,
+  Scissor = 3
+
+let shapeTable = {
+  "A": Rock,
+  "B": Paper,
+  "C": Scissor,
+  "X": Rock,
+  "Y": Paper,
+  "Z": Scissor
+}.toTable
+
+let scoringTable = {
+  Rock: {
+    Rock: 3,
+    Paper: 0,
+    Scissor: 6
+  }.toTable,
+  Paper: {
+    Rock: 6,
+    Paper: 3,
+    Scissor: 0
+  }.toTable,
+  Scissor: {
+    Rock: 0,
+    Paper: 6,
+    Scissor: 3
+  }.toTable
+}.toTable
+
+type Response {.pure.} = enum
+  Lose = 0,
+  Draw = 3,
+  Win = 6
+
+let resultTable = {
+  "X": Lose,
+  "Y": Draw,
+  "Z": Win
+}.toTable
+
+let responseShape = {
+  Lose: {
+    Rock: Scissor,
+    Paper: Rock,
+    Scissor: Paper
+  }.toTable,
+  Draw: {
+    Rock: Rock,
+    Paper: Paper,
+    Scissor: Scissor
+  }.toTable,
+  Win: {
+    Rock: Paper,
+    Paper: Scissor,
+    Scissor: Rock
+  }.toTable
+}.toTable
+
+const strategyGuide: seq[string] = readFile("day_02/input.txt").splitLines
+
+proc solveTotalScore() =
+  var score = 0
+  for step in strategyGuide:
+    let opponent = shapeTable[step.substr(0, 0)]
+    let response = shapeTable[step.substr(2, 2)]
+    score += response.int
+    score += scoringTable[response][opponent]
+  echo "Total socre: " & $score
+
+proc solveDecryptedScore() =
+  var score = 0
+  for step in strategyGuide:
+    let opponent = shapeTable[step.substr(0, 0)]
+    let desiredResult = resultTable[step.substr(2, 2)]
+    let response = responseShape[desiredResult][opponent]
+    score += response.int
+    score += desiredResult.int
+  echo "Descrypted score: " & $score
+  
+
+if isMainModule:
+  solveTotalScore()
+  solveDecryptedScore()