Day 22

AdventOfCode2020.xcodeproj/project.pbxproj

@@ -32,6 +32,9 @@
 		26DD9CA92590759B0082D4F2 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26DD9CA82590759B0082D4F2 /* main.swift */; };
 		26DD9CC2259075A50082D4F2 /* LoadData.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2AD3A2581713A00702405 /* LoadData.swift */; };
 		26DD9CD82590767F0082D4F2 /* Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2ACE5257ED09000702405 /* Extensions.swift */; };
+		26DD9CF52591C4000082D4F2 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26DD9CF42591C4000082D4F2 /* main.swift */; };
+		26DD9D0F2591C40C0082D4F2 /* Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2ACE5257ED09000702405 /* Extensions.swift */; };
+		26DD9D102591C40C0082D4F2 /* LoadData.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2AD3A2581713A00702405 /* LoadData.swift */; };
 		26E2ACD8257ECFFA00702405 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2ACD7257ECFFA00702405 /* main.swift */; };
 		26E2ACE6257ED09000702405 /* Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2ACE5257ED09000702405 /* Extensions.swift */; };
 		26E2ACE7257ED09000702405 /* Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 26E2ACE5257ED09000702405 /* Extensions.swift */; };
@@ -190,6 +193,15 @@
 			);
 			runOnlyForDeploymentPostprocessing = 1;
 		};
+		26DD9CF02591C4000082D4F2 /* CopyFiles */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = /usr/share/man/man1/;
+			dstSubfolderSpec = 0;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 1;
+		};
 		26E2ACD3257ECFFA00702405 /* CopyFiles */ = {
 			isa = PBXCopyFilesBuildPhase;
 			buildActionMask = 2147483647;
@@ -291,6 +303,8 @@
 		26DD9C73258F2CEE0082D4F2 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
 		26DD9CA62590759B0082D4F2 /* day21 */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = day21; sourceTree = BUILT_PRODUCTS_DIR; };
 		26DD9CA82590759B0082D4F2 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
+		26DD9CF22591C4000082D4F2 /* day22 */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = day22; sourceTree = BUILT_PRODUCTS_DIR; };
+		26DD9CF42591C4000082D4F2 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
 		26E2ACD5257ECFFA00702405 /* day8 */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = day8; sourceTree = BUILT_PRODUCTS_DIR; };
 		26E2ACD7257ECFFA00702405 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
 		26E2ACE5257ED09000702405 /* Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Extensions.swift; sourceTree = "<group>"; };
@@ -403,6 +417,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		26DD9CEF2591C4000082D4F2 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		26E2ACD2257ECFFA00702405 /* Frameworks */ = {
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
@@ -503,6 +524,7 @@
 				26DD9C3F258DEAC70082D4F2 /* day19 */,
 				26DD9C72258F2CEE0082D4F2 /* day20 */,
 				26DD9CA72590759B0082D4F2 /* day21 */,
+				26DD9CF32591C4000082D4F2 /* day22 */,
 				268D953A25781DD80030EC4D /* Products */,
 			);
 			sourceTree = "<group>";
@@ -531,6 +553,7 @@
 				26DD9C3E258DEAC70082D4F2 /* day19 */,
 				26DD9C71258F2CEE0082D4F2 /* day20 */,
 				26DD9CA62590759B0082D4F2 /* day21 */,
+				26DD9CF22591C4000082D4F2 /* day22 */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -623,6 +646,14 @@
 			path = day21;
 			sourceTree = "<group>";
 		};
+		26DD9CF32591C4000082D4F2 /* day22 */ = {
+			isa = PBXGroup;
+			children = (
+				26DD9CF42591C4000082D4F2 /* main.swift */,
+			);
+			path = day22;
+			sourceTree = "<group>";
+		};
 		26E2ACD6257ECFFA00702405 /* day8 */ = {
 			isa = PBXGroup;
 			children = (
@@ -920,6 +951,23 @@
 			productReference = 26DD9CA62590759B0082D4F2 /* day21 */;
 			productType = "com.apple.product-type.tool";
 		};
+		26DD9CF12591C4000082D4F2 /* day22 */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 26DD9CF82591C4000082D4F2 /* Build configuration list for PBXNativeTarget "day22" */;
+			buildPhases = (
+				26DD9CEE2591C4000082D4F2 /* Sources */,
+				26DD9CEF2591C4000082D4F2 /* Frameworks */,
+				26DD9CF02591C4000082D4F2 /* CopyFiles */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = day22;
+			productName = day22;
+			productReference = 26DD9CF22591C4000082D4F2 /* day22 */;
+			productType = "com.apple.product-type.tool";
+		};
 		26E2ACD4257ECFFA00702405 /* day8 */ = {
 			isa = PBXNativeTarget;
 			buildConfigurationList = 26E2ACDB257ECFFA00702405 /* Build configuration list for PBXNativeTarget "day8" */;
@@ -1104,6 +1152,9 @@
 					26DD9CA52590759B0082D4F2 = {
 						CreatedOnToolsVersion = 12.3;
 					};
+					26DD9CF12591C4000082D4F2 = {
+						CreatedOnToolsVersion = 12.3;
+					};
 					26E2ACD4257ECFFA00702405 = {
 						CreatedOnToolsVersion = 12.2;
 					};
@@ -1164,6 +1215,7 @@
 				26DD9C3D258DEAC70082D4F2 /* day19 */,
 				26DD9C70258F2CEE0082D4F2 /* day20 */,
 				26DD9CA52590759B0082D4F2 /* day21 */,
+				26DD9CF12591C4000082D4F2 /* day22 */,
 			);
 		};
 /* End PBXProject section */
@@ -1299,6 +1351,16 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		26DD9CEE2591C4000082D4F2 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				26DD9CF52591C4000082D4F2 /* main.swift in Sources */,
+				26DD9D0F2591C40C0082D4F2 /* Extensions.swift in Sources */,
+				26DD9D102591C40C0082D4F2 /* LoadData.swift in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		26E2ACD1257ECFFA00702405 /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -1801,6 +1863,28 @@
 			};
 			name = Release;
 		};
+		26DD9CF62591C4000082D4F2 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = 722B335UM5;
+				ENABLE_HARDENED_RUNTIME = YES;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 5.0;
+			};
+			name = Debug;
+		};
+		26DD9CF72591C4000082D4F2 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = 722B335UM5;
+				ENABLE_HARDENED_RUNTIME = YES;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 5.0;
+			};
+			name = Release;
+		};
 		26E2ACD9257ECFFA00702405 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
@@ -2122,6 +2206,15 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		26DD9CF82591C4000082D4F2 /* Build configuration list for PBXNativeTarget "day22" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				26DD9CF62591C4000082D4F2 /* Debug */,
+				26DD9CF72591C4000082D4F2 /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 		26E2ACDB257ECFFA00702405 /* Build configuration list for PBXNativeTarget "day8" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (

day22/main.swift

@@ -0,0 +1,87 @@
+import Foundation
+let data = loadData(day: 22)
+let scanner = Scanner(string: data)
+
+
+guard scanner.string("Player 1:") else { fatalError() }
+let p1 = scanner.integers()
+var player1Deck = p1
+
+guard scanner.string("Player 2:") else { fatalError() }
+let p2 = scanner.integers()
+var player2Deck = p2
+
+assert(player1Deck.count == player2Deck.count)
+
+while !player1Deck.isEmpty && !player2Deck.isEmpty {
+    let a = player1Deck.removeFirst()
+    let b = player2Deck.removeFirst()
+
+    if a > b {
+        player1Deck.append(contentsOf: [a, b])
+    } else {
+        player2Deck.append(contentsOf: [b, a])
+    }
+}
+
+func calculateScore(_ deck: [Int]) -> Int {
+    deck.reversed().enumerated().reduce(0) { $0 + $1.element * ($1.offset + 1) }
+}
+
+if player2Deck.isEmpty {
+    print("Player 1 wins", calculateScore(player1Deck))
+} else {
+    print("Player 2 wins", calculateScore(player2Deck))
+}
+
+struct PlayedDeck: Hashable {
+    let player1: [Int]
+    let player2: [Int]
+}
+var playedDecks: Set<PlayedDeck> = []
+
+
+func playGame(deck1: [Int], deck2: [Int])  -> (winner: Bool, score: Int) {
+    var deck1 = deck1
+    var deck2 = deck2
+    var playedDecks: Set<PlayedDeck> = []
+
+    while !deck1.isEmpty && !deck2.isEmpty {
+        if !playedDecks.insert(PlayedDeck(player1: deck1, player2: deck2)).inserted {
+            return (true, calculateScore(deck1))
+        }
+        playRound(deck1: &deck1, deck2: &deck2)
+    }
+
+    let winner = deck2.isEmpty
+    return (winner, winner ? calculateScore(deck1) : calculateScore(deck2))
+}
+
+func playRound(deck1: inout [Int], deck2: inout [Int]) {
+    let a = deck1.removeFirst()
+    let b = deck2.removeFirst()
+
+    let winner: Bool
+    if a <= deck1.count && b <= deck2.count {
+        winner = playGame(deck1: Array(deck1[0..<a]), deck2: Array(deck2[0..<b])).winner
+    } else {
+        winner = a > b
+    }
+
+    if winner {
+        deck1.append(contentsOf: [a, b])
+    } else {
+        deck2.append(contentsOf: [b, a])
+    }
+}
+
+
+player1Deck = p1
+player2Deck = p2
+
+    let (winner, score) = playGame(deck1: p1, deck2: p2)
+    if winner {
+        print("Player 1 wins", score)
+    } else {
+        print("Player 2 wins", score)
+    }