02/code.go

@@ -0,0 +1,163 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+type Cube struct {
+	count int
+	color string
+}
+
+type Game struct {
+	id   int
+	sets [][]Cube
+}
+
+func readInput(file *os.File) []Game {
+	scanner := bufio.NewScanner(file)
+	var games []Game
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			break
+		}
+
+		var current Game
+		n, err := fmt.Sscanf(line, "Game %d:", &current.id)
+		if n != 1 || err != nil {
+			log.Fatalf("Failed to read game: %s\n%s", line, err)
+		}
+
+		gameParts := strings.Split(line, ":")
+		if len(gameParts) != 2 {
+			log.Fatalf("Wrong input: %s", line)
+		}
+
+		sets := strings.Split(gameParts[1], ";")
+		if len(sets) == 0 {
+			log.Fatalf("Wrong input: %s", gameParts[1])
+		}
+
+		for i := range sets {
+			var set []Cube
+			cubes := strings.Split(sets[i], ",")
+			if len(cubes) == 0 {
+				log.Fatalf("Wrong input: %s", sets[i])
+			}
+
+			for j := range cubes {
+				var cube Cube
+				n, err = fmt.Sscanf(cubes[j], "%d %s", &cube.count, &cube.color)
+				if n != 2 || err != nil {
+					log.Fatalf("Wrong input: %s\n%s", cubes[j], err)
+				}
+
+				set = append(set, cube)
+			}
+
+			current.sets = append(current.sets, set)
+		}
+
+		games = append(games, current)
+	}
+
+	return games
+}
+
+type Limits struct {
+	red, green, blue int
+}
+
+func checkLimits(sets [][]Cube, limits Limits) bool {
+	for i := range sets {
+		for j := range sets[i] {
+			switch sets[i][j].color {
+			case "red":
+				if sets[i][j].count > limits.red {
+					return false
+				}
+			case "green":
+				if sets[i][j].count > limits.green {
+					return false
+				}
+			case "blue":
+				if sets[i][j].count > limits.blue {
+					return false
+				}
+			}
+		}
+	}
+
+	return true
+}
+
+func part1(games []Game) int {
+	limits := Limits{red: 12, green: 13, blue: 14}
+	var result int
+
+	for i := range games {
+		if checkLimits(games[i].sets, limits) {
+			result += games[i].id
+		}
+	}
+
+	return result
+}
+
+func getLimits(sets [][]Cube) Limits {
+	var limits Limits
+	for i := range sets {
+		for j := range sets[i] {
+			switch sets[i][j].color {
+			case "red":
+				if sets[i][j].count > limits.red {
+					limits.red = sets[i][j].count
+				}
+			case "green":
+				if sets[i][j].count > limits.green {
+					limits.green = sets[i][j].count
+				}
+			case "blue":
+				if sets[i][j].count > limits.blue {
+					limits.blue = sets[i][j].count
+				}
+			}
+		}
+	}
+
+	return limits
+}
+
+func part2(games []Game) int {
+	var result int
+
+	for i := range games {
+		limits := getLimits(games[i].sets)
+		result += limits.red * limits.green * limits.blue
+	}
+
+	return result
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("You need to specify a file!")
+	}
+
+	filePath := os.Args[1]
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatalf("Failed to open %s!\n", filePath)
+
+	}
+
+	games := readInput(file)
+	fmt.Println("Part1:", part1(games))
+	fmt.Println("Part2:", part2(games))
+}

02/description.txt

@@ -0,0 +1,56 @@
+--- Day 2: Cube Conundrum ---
+
+You're launched high into the atmosphere! The apex of your trajectory just barely reaches the surface of a large island floating in the sky. You gently land in a fluffy pile of leaves. It's quite cold, but you don't see much snow. An Elf runs over to greet you.
+
+The Elf explains that you've arrived at Snow Island and apologizes for the lack of snow. He'll be happy to explain the situation, but it's a bit of a walk, so you have some time. They don't get many visitors up here; would you like to play a game in the meantime?
+
+As you walk, the Elf shows you a small bag and some cubes which are either red, green, or blue. Each time you play this game, he will hide a secret number of cubes of each color in the bag, and your goal is to figure out information about the number of cubes.
+
+To get information, once a bag has been loaded with cubes, the Elf will reach into the bag, grab a handful of random cubes, show them to you, and then put them back in the bag. He'll do this a few times per game.
+
+You play several games and record the information from each game (your puzzle input). Each game is listed with its ID number (like the 11 in Game 11: ...) followed by a semicolon-separated list of subsets of cubes that were revealed from the bag (like 3 red, 5 green, 4 blue).
+
+For example, the record of a few games might look like this:
+
+Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+
+In game 1, three sets of cubes are revealed from the bag (and then put back again). The first set is 3 blue cubes and 4 red cubes; the second set is 1 red cube, 2 green cubes, and 6 blue cubes; the third set is only 2 green cubes.
+
+The Elf would first like to know which games would have been possible if the bag contained only 12 red cubes, 13 green cubes, and 14 blue cubes?
+
+In the example above, games 1, 2, and 5 would have been possible if the bag had been loaded with that configuration. However, game 3 would have been impossible because at one point the Elf showed you 20 red cubes at once; similarly, game 4 would also have been impossible because the Elf showed you 15 blue cubes at once. If you add up the IDs of the games that would have been possible, you get 8.
+
+Determine which games would have been possible if the bag had been loaded with only 12 red cubes, 13 green cubes, and 14 blue cubes. What is the sum of the IDs of those games?
+
+Your puzzle answer was 2061.
+--- Part Two ---
+
+The Elf says they've stopped producing snow because they aren't getting any water! He isn't sure why the water stopped; however, he can show you how to get to the water source to check it out for yourself. It's just up ahead!
+
+As you continue your walk, the Elf poses a second question: in each game you played, what is the fewest number of cubes of each color that could have been in the bag to make the game possible?
+
+Again consider the example games from earlier:
+
+Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+
+    In game 1, the game could have been played with as few as 4 red, 2 green, and 6 blue cubes. If any color had even one fewer cube, the game would have been impossible.
+    Game 2 could have been played with a minimum of 1 red, 3 green, and 4 blue cubes.
+    Game 3 must have been played with at least 20 red, 13 green, and 6 blue cubes.
+    Game 4 required at least 14 red, 3 green, and 15 blue cubes.
+    Game 5 needed no fewer than 6 red, 3 green, and 2 blue cubes in the bag.
+
+The power of a set of cubes is equal to the numbers of red, green, and blue cubes multiplied together. The power of the minimum set of cubes in game 1 is 48. In games 2-5 it was 12, 1560, 630, and 36, respectively. Adding up these five powers produces the sum 2286.
+
+For each game, find the minimum set of cubes that must have been present. What is the sum of the power of these sets?
+
+Your puzzle answer was 72596.
+
+Both parts of this puzzle are complete! They provide two gold stars: **

02/input

@@ -0,0 +1,100 @@
+Game 1: 4 red, 5 blue, 4 green; 7 red, 8 blue, 2 green; 9 blue, 6 red; 1 green, 3 red, 7 blue; 3 green, 7 red
+Game 2: 20 blue, 12 green, 2 red; 1 red, 2 green, 20 blue; 1 red, 14 green, 17 blue; 7 green, 17 blue
+Game 3: 3 green, 4 red; 10 red, 2 blue, 5 green; 9 red, 3 blue, 5 green
+Game 4: 10 green, 1 blue, 3 red; 1 red, 12 green, 1 blue; 1 blue, 2 green; 4 green, 3 red
+Game 5: 3 green, 8 red, 1 blue; 4 blue, 7 red, 3 green; 2 green, 2 blue, 13 red
+Game 6: 1 green, 4 red, 2 blue; 9 blue, 1 red; 2 green, 4 blue; 4 red, 11 blue; 9 blue, 3 red
+Game 7: 13 red, 18 green, 4 blue; 15 red, 5 blue, 14 green; 15 red, 11 green, 7 blue; 3 green, 3 red, 7 blue; 3 red, 5 blue, 9 green
+Game 8: 1 red, 4 green, 4 blue; 15 red, 8 green; 6 green, 1 blue, 15 red; 6 blue, 15 green, 6 red; 2 red, 1 blue, 9 green
+Game 9: 18 red, 8 green; 2 green, 18 red, 9 blue; 14 red, 2 blue, 10 green; 4 red, 2 green, 4 blue; 4 blue, 12 red, 9 green
+Game 10: 4 green, 1 blue; 3 blue, 2 green, 12 red; 15 blue, 12 red, 2 green; 10 red, 8 green, 11 blue; 8 green, 10 blue, 10 red
+Game 11: 5 blue, 7 red; 2 green, 1 blue, 12 red; 7 green, 8 red, 4 blue; 3 blue, 8 red; 6 green, 9 red, 3 blue; 11 green, 12 red
+Game 12: 1 blue, 3 green; 3 red, 6 green; 2 green; 1 red, 6 green; 1 green, 3 red; 1 blue, 2 green, 2 red
+Game 13: 3 blue, 12 red, 12 green; 5 green, 3 blue, 2 red; 3 green, 7 blue, 13 red; 4 green, 7 red; 3 green, 3 blue, 5 red
+Game 14: 14 blue, 1 red, 6 green; 3 red, 9 blue; 5 green, 11 blue, 3 red
+Game 15: 9 blue, 2 red, 5 green; 8 blue, 3 red, 6 green; 17 red, 2 green, 7 blue; 11 red, 2 green, 9 blue; 1 red, 4 green
+Game 16: 2 green, 2 red; 3 red, 2 blue, 2 green; 5 red, 2 blue, 2 green; 2 red; 2 green, 7 blue, 4 red
+Game 17: 8 blue, 6 green, 11 red; 5 red, 2 green, 2 blue; 4 green, 15 red, 10 blue; 6 blue, 2 red, 6 green
+Game 18: 1 green, 11 blue, 1 red; 1 green, 1 blue, 4 red; 10 blue, 2 green; 3 green, 12 red; 4 green, 8 red, 5 blue; 13 blue, 4 red, 3 green
+Game 19: 5 green, 3 blue, 5 red; 5 green, 15 blue, 10 red; 15 blue, 12 red, 1 green; 7 red, 5 green, 10 blue
+Game 20: 4 red, 9 green, 9 blue; 5 red, 10 green, 10 blue; 3 blue, 11 green
+Game 21: 13 blue, 9 green, 13 red; 1 blue, 11 green, 14 red; 14 blue, 8 red, 9 green
+Game 22: 8 red, 12 blue, 6 green; 12 blue, 10 green, 4 red; 14 green, 16 blue, 3 red; 2 blue, 8 red, 5 green; 12 blue, 9 green, 9 red
+Game 23: 9 red; 3 blue, 11 red; 2 red, 7 blue; 5 red, 4 blue, 1 green; 4 red; 7 blue, 12 red
+Game 24: 5 green, 7 blue, 3 red; 5 green, 3 red, 13 blue; 11 red, 2 green, 4 blue; 11 blue, 1 green, 13 red; 3 green, 9 red, 5 blue; 1 green, 9 red, 17 blue
+Game 25: 5 blue, 12 green, 4 red; 2 blue, 2 red, 9 green; 8 blue, 16 green, 4 red
+Game 26: 7 blue, 2 green; 5 blue, 1 green; 1 red, 2 green; 8 blue, 1 green
+Game 27: 1 blue, 4 red, 17 green; 3 red, 2 blue; 18 green, 1 blue; 3 red, 7 green; 1 green, 3 red, 3 blue
+Game 28: 6 green, 1 blue, 7 red; 10 red, 9 green; 10 red, 9 green, 1 blue; 3 blue, 19 red; 12 red, 3 blue, 14 green
+Game 29: 4 red, 7 green, 11 blue; 2 red, 3 green, 1 blue; 1 red, 5 blue, 18 green; 11 green, 4 red, 6 blue; 6 blue, 3 red, 11 green; 5 blue, 17 green, 2 red
+Game 30: 1 red, 15 green, 1 blue; 2 blue, 1 red, 12 green; 6 red, 8 green, 1 blue; 2 blue, 4 red, 11 green; 2 blue, 5 green, 5 red
+Game 31: 9 blue, 6 red, 7 green; 4 green, 2 red; 11 blue
+Game 32: 15 green, 1 blue, 11 red; 1 blue, 7 red, 13 green; 2 blue, 9 green, 3 red; 2 blue, 13 red, 18 green
+Game 33: 2 red, 2 green, 4 blue; 2 green, 7 blue, 4 red; 3 blue, 2 green
+Game 34: 1 green, 3 red; 13 green; 2 red, 14 green; 2 blue, 14 green; 6 green, 3 red, 1 blue
+Game 35: 2 blue; 8 blue, 3 green, 3 red; 15 blue, 2 red; 12 blue, 1 green; 3 blue, 2 green; 2 red, 8 blue
+Game 36: 4 green, 1 red, 1 blue; 16 green, 3 red; 18 green, 4 red; 4 green
+Game 37: 6 red, 1 blue, 3 green; 2 blue, 3 red, 2 green; 2 red, 1 blue, 9 green; 2 red, 8 green; 2 blue, 2 red; 1 red, 1 green, 1 blue
+Game 38: 9 red, 1 green; 14 red, 1 green; 6 green, 3 red; 1 blue, 3 red, 5 green; 5 green, 12 red
+Game 39: 13 blue, 2 red, 3 green; 5 green, 8 blue, 8 red; 11 blue, 7 green
+Game 40: 1 green, 7 blue, 6 red; 4 green, 1 red, 5 blue; 7 blue, 2 red
+Game 41: 12 red, 5 green, 6 blue; 12 blue, 7 red, 4 green; 7 green, 9 blue, 14 red; 1 green, 6 blue, 4 red; 1 blue, 6 red, 6 green
+Game 42: 9 red, 2 blue, 11 green; 5 blue, 6 red, 7 green; 5 blue, 2 red, 3 green; 7 green, 7 blue, 1 red; 11 green, 12 blue, 4 red; 2 blue, 6 red, 10 green
+Game 43: 8 green, 7 red, 7 blue; 7 red, 11 green, 2 blue; 17 red, 12 blue; 10 blue, 5 green, 3 red; 2 green, 4 red; 16 green, 10 red, 2 blue
+Game 44: 6 blue, 16 green; 7 green, 4 blue, 6 red; 8 red, 5 blue, 7 green; 6 green, 6 red, 6 blue; 10 green, 1 red, 9 blue
+Game 45: 10 blue, 4 green, 10 red; 5 green, 9 blue, 3 red; 8 blue, 9 green, 10 red; 7 green, 4 red, 3 blue; 2 blue, 5 green, 9 red
+Game 46: 11 green, 1 blue, 3 red; 3 green, 4 blue, 5 red; 5 blue, 10 green, 3 red; 17 red, 4 blue, 5 green; 8 red, 1 blue, 6 green; 9 red, 9 green, 1 blue
+Game 47: 2 blue, 16 green, 11 red; 1 blue, 7 green, 4 red; 1 green, 3 blue, 9 red; 2 blue, 8 green, 1 red; 14 red, 3 blue, 5 green
+Game 48: 6 blue, 7 red; 2 green, 1 red, 1 blue; 2 green, 3 red, 2 blue; 5 blue, 8 red; 4 red, 5 green, 1 blue
+Game 49: 7 green, 3 blue, 11 red; 5 green, 10 red, 8 blue; 6 green, 18 red; 7 green, 9 blue, 14 red; 5 green, 6 blue, 3 red
+Game 50: 3 green, 1 red, 6 blue; 1 blue, 4 green, 13 red; 12 blue, 10 green, 3 red; 18 blue, 4 green, 14 red; 4 green, 6 blue, 7 red
+Game 51: 2 green, 4 red; 1 green, 12 red; 1 blue, 12 red, 5 green; 1 blue, 9 red, 2 green
+Game 52: 1 red, 2 green, 9 blue; 6 blue, 5 green, 3 red; 3 red, 8 blue, 4 green; 4 green, 1 blue, 4 red; 2 green, 5 blue; 2 red, 3 green, 6 blue
+Game 53: 1 blue, 16 red; 8 red, 4 green; 2 green, 3 red; 2 green, 2 blue; 20 red, 4 green, 1 blue; 1 green, 15 red
+Game 54: 1 red, 8 blue; 2 red, 1 green, 6 blue; 9 red, 9 blue
+Game 55: 1 red, 6 green, 1 blue; 1 green, 1 red, 2 blue; 1 red, 5 blue; 1 green, 1 red; 2 green
+Game 56: 8 blue, 8 green, 7 red; 3 red, 1 blue, 9 green; 4 green, 5 red, 12 blue
+Game 57: 11 green, 16 blue, 5 red; 9 green, 13 blue; 16 blue, 4 red, 15 green; 17 green, 7 red, 15 blue; 1 red, 9 green, 5 blue; 18 blue
+Game 58: 2 green, 2 blue, 1 red; 7 green, 3 red, 5 blue; 6 green, 1 blue, 2 red; 5 green, 4 blue; 2 blue, 6 green
+Game 59: 8 green, 11 blue; 13 blue, 4 green, 3 red; 6 green, 19 blue, 14 red
+Game 60: 6 red, 4 green, 4 blue; 12 green, 2 blue, 13 red; 2 green, 1 red; 3 green, 9 red; 1 red, 1 blue, 2 green
+Game 61: 10 green, 1 blue, 1 red; 11 green, 7 blue; 2 red, 3 green, 6 blue
+Game 62: 5 green, 7 blue, 3 red; 9 blue, 7 green, 3 red; 5 red, 2 green, 12 blue; 14 blue, 10 red, 7 green; 3 blue, 1 green, 10 red
+Game 63: 1 red, 4 green, 6 blue; 2 blue, 14 red, 1 green; 1 red, 4 green, 3 blue; 1 red, 2 blue, 1 green; 4 blue, 11 red, 6 green; 3 green, 7 blue, 1 red
+Game 64: 14 red, 4 green, 5 blue; 7 red, 5 green, 6 blue; 8 blue, 8 red, 1 green
+Game 65: 3 blue, 6 green, 1 red; 2 blue, 10 green; 16 green, 1 blue, 1 red; 20 green
+Game 66: 7 red, 4 blue; 4 blue, 8 red; 2 blue, 3 green, 7 red; 7 red, 1 green, 4 blue; 3 green, 5 red
+Game 67: 2 green, 14 red, 5 blue; 20 red, 15 blue, 2 green; 15 blue, 15 red, 1 green
+Game 68: 6 green, 9 red, 7 blue; 3 green, 9 red, 13 blue; 9 blue, 4 red; 2 red, 4 blue; 6 green, 9 red; 2 green, 6 blue
+Game 69: 8 green, 1 blue, 11 red; 7 blue, 2 red, 11 green; 7 blue, 14 green; 2 red, 10 blue, 8 green; 14 red, 4 green, 5 blue; 16 red, 5 blue, 7 green
+Game 70: 7 green, 11 red; 11 green, 2 blue; 11 green, 17 red, 8 blue; 4 green, 7 blue
+Game 71: 4 blue, 4 red, 2 green; 2 green, 6 red, 5 blue; 1 green, 2 red; 2 green, 6 blue, 2 red; 2 green
+Game 72: 1 green, 1 red, 1 blue; 1 green, 4 red, 1 blue; 2 green, 1 blue, 5 red; 3 red; 2 green, 1 blue, 1 red
+Game 73: 10 blue, 2 green, 3 red; 13 blue, 13 green, 4 red; 2 red, 8 green; 11 green, 1 red, 1 blue; 14 green, 15 blue, 4 red
+Game 74: 3 green, 1 blue, 7 red; 15 green, 4 red, 1 blue; 3 red, 6 green
+Game 75: 15 red; 15 red, 4 blue; 14 red, 3 blue, 1 green; 8 red, 1 green, 2 blue; 1 green, 13 red, 1 blue
+Game 76: 4 blue, 7 green, 1 red; 1 red, 1 green, 10 blue; 2 green, 3 blue; 9 green; 4 green, 11 blue; 6 blue, 3 green
+Game 77: 2 red, 8 blue, 12 green; 10 green, 2 blue; 7 green, 1 blue, 4 red; 3 green, 2 red; 13 green, 4 blue, 3 red
+Game 78: 8 blue, 2 green; 1 green, 5 blue, 2 red; 3 red, 3 green; 3 blue, 1 red, 5 green; 3 blue, 4 green, 3 red; 3 red
+Game 79: 8 green, 5 red, 2 blue; 1 blue, 6 red; 9 green, 2 red; 1 blue, 8 green, 8 red; 6 green, 1 red; 2 red, 9 green
+Game 80: 2 blue, 11 red, 15 green; 6 blue, 9 red, 19 green; 16 green, 3 red
+Game 81: 15 blue, 18 red; 18 red, 2 green; 7 red, 2 green, 11 blue; 17 blue, 8 red; 8 green, 8 red; 2 red, 10 green
+Game 82: 6 blue, 1 red; 2 red, 5 green, 8 blue; 3 blue, 5 green; 1 green, 2 red, 2 blue; 2 red, 4 green, 5 blue
+Game 83: 1 red, 16 green, 7 blue; 1 blue, 4 red, 4 green; 4 blue, 5 red, 1 green; 1 red, 7 blue, 11 green; 6 red, 7 blue, 2 green
+Game 84: 3 red, 4 green, 16 blue; 3 blue, 2 green, 2 red; 10 green, 15 blue, 3 red
+Game 85: 7 red, 2 blue, 15 green; 1 red, 12 green, 6 blue; 5 red, 16 green, 1 blue; 8 blue, 10 green, 3 red; 3 blue, 2 red; 5 blue, 16 green, 4 red
+Game 86: 10 red, 3 blue, 4 green; 1 red, 2 blue, 3 green; 15 red, 1 blue; 2 green, 2 red, 2 blue; 4 red, 4 green, 1 blue; 3 green, 2 red, 3 blue
+Game 87: 19 blue, 2 green; 12 blue; 15 red, 2 green, 20 blue; 14 blue, 9 red; 6 blue, 3 green
+Game 88: 19 green, 4 red; 2 green, 7 blue, 17 red; 7 blue, 9 green, 8 red; 9 blue, 5 red, 14 green; 11 red, 9 blue, 19 green
+Game 89: 20 blue, 13 green; 4 green, 5 red, 14 blue; 3 blue; 4 green, 5 blue; 3 red, 6 blue, 7 green
+Game 90: 1 blue, 12 red; 3 green, 9 blue, 8 red; 2 blue, 3 green, 10 red; 8 blue, 5 red, 1 green
+Game 91: 4 blue, 2 red, 5 green; 5 blue, 5 green, 2 red; 3 blue, 14 green, 3 red; 8 green, 1 red, 8 blue; 8 green, 2 red, 3 blue; 19 green, 8 blue, 10 red
+Game 92: 11 green, 8 red, 5 blue; 12 green, 14 blue, 11 red; 4 green, 16 red
+Game 93: 13 blue, 3 red, 3 green; 2 green, 6 blue, 3 red; 2 red, 19 blue, 5 green
+Game 94: 5 green, 7 red, 10 blue; 5 blue, 8 red, 8 green; 5 blue, 6 red, 4 green; 12 blue, 9 red, 4 green; 6 blue, 5 green, 5 red; 8 green, 10 red
+Game 95: 1 red, 4 green, 10 blue; 7 blue, 5 green, 3 red; 13 blue, 2 red, 4 green
+Game 96: 2 green, 1 red; 5 green, 10 blue; 3 blue, 5 green; 1 red; 2 blue, 6 green
+Game 97: 6 green, 12 red, 8 blue; 4 green, 7 red, 7 blue; 1 green, 4 red, 9 blue; 7 red, 4 green; 6 blue, 10 red, 15 green
+Game 98: 3 green, 5 red; 12 red, 11 green, 1 blue; 16 red, 4 green, 1 blue
+Game 99: 8 blue, 7 green; 1 green, 5 red, 3 blue; 7 green, 1 red, 2 blue; 5 green, 3 red, 12 blue; 2 green, 7 blue, 3 red
+Game 100: 4 blue, 1 green; 13 red, 2 blue; 16 red; 15 red, 2 blue; 9 red, 1 green, 1 blue; 7 red, 4 blue

03/code.go

@@ -0,0 +1,232 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+)
+
+func readInput(file *os.File) []string {
+	scanner := bufio.NewScanner(file)
+	var lines []string
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			break
+		}
+
+		lines = append(lines, line)
+	}
+
+	return lines
+}
+
+const firstDigit = 48
+const lastDigit = 57
+
+func isDigit(b byte) bool {
+	return firstDigit <= b && b <= lastDigit
+}
+
+func isSymbol(b byte) bool {
+	return !isDigit(b) && b != '.'
+}
+
+func symbolNear(lines []string, height int, width int, y int, start int, end int) bool {
+	i := start - 1
+	if i < 0 {
+		i = start
+	}
+
+	if end >= width {
+		end = width - 1
+	}
+
+	canGoUp := y-1 >= 0
+	canGoDown := y+1 < height
+
+	for ; i <= end; i++ {
+		if isSymbol(lines[y][i]) {
+			return true
+		}
+
+		if canGoUp && isSymbol(lines[y-1][i]) {
+			return true
+		}
+
+		if canGoDown && isSymbol(lines[y+1][i]) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func numberFromLine(lines []string, index int, start int, end int) int {
+	var number int
+	n, err := fmt.Sscanf(lines[index][start:end], "%d", &number)
+	if n != 1 || err != nil {
+		log.Fatalf("Wrong input: %s\n%s", lines[index][start:end], err)
+	}
+
+	return number
+}
+
+func part1(lines []string) int {
+	var result int
+	height := len(lines)
+	width := len(lines[0])
+	edge := width - 1
+	for i := range lines {
+		var start, end int
+		gotNumber := false
+		tryRead := false
+		for j := range lines[i] {
+			if isDigit(lines[i][j]) {
+				if !gotNumber {
+					start = j
+					gotNumber = true
+				}
+
+				if j == edge {
+					end = j + 1
+					tryRead = true
+				}
+			} else {
+				if !gotNumber {
+					continue
+				}
+
+				end = j
+				gotNumber = false
+				tryRead = true
+			}
+
+			if tryRead {
+				if symbolNear(lines, height, width, i, start, end) {
+					result += numberFromLine(lines, i, start, end)
+				}
+
+				tryRead = false
+			}
+
+		}
+	}
+
+	return result
+}
+
+type Point struct {
+	x, y int
+}
+
+func digitsFromLine(line string, start int, end int, y int) []Point {
+	var points []Point
+	reading := false
+	for i := start; i <= end; i++ {
+		if isDigit(line[i]) {
+			if !reading {
+				points = append(points, Point{x: i, y: y})
+				reading = true
+			}
+		} else {
+			reading = false
+		}
+	}
+
+	return points
+}
+
+func getDigits(lines []string, height int, width int, y int, x int) []Point {
+	var points []Point
+
+	start := x - 1
+	if start < 0 {
+		start = x
+	}
+
+	end := x + 1
+	if end >= width {
+		end = x
+	}
+
+	if y-1 >= 0 {
+		points = append(points, digitsFromLine(lines[y-1], start, end, y-1)...)
+	}
+
+	if y+1 < height {
+		points = append(points, digitsFromLine(lines[y+1], start, end, y+1)...)
+	}
+
+	points = append(points, digitsFromLine(lines[y], start, end, y)...)
+
+	return points
+}
+
+func numberFromPoint(lines []string, width int, point Point) int {
+	start := point.x
+	end := point.x
+	var haveStart, haveEnd bool
+	for {
+		if haveStart && haveEnd {
+			break
+		}
+
+		if !haveStart && start-1 >= 0 && isDigit(lines[point.y][start-1]) {
+			start--
+		} else {
+			haveStart = true
+		}
+
+		if !haveEnd && end+1 < width && isDigit(lines[point.y][end+1]) {
+			end++
+		} else {
+			haveEnd = true
+		}
+	}
+	end++
+
+	return numberFromLine(lines, point.y, start, end)
+}
+
+func part2(lines []string) int {
+	height := len(lines)
+	width := len(lines[0])
+	var result int
+	for i := range lines {
+		for j := range lines[i] {
+			if lines[i][j] == '*' {
+				digits := getDigits(lines, height, width, i, j)
+				if len(digits) == 2 {
+					prod := 1
+					for k := range digits {
+						prod *= numberFromPoint(lines, width, digits[k])
+					}
+
+					result += prod
+				}
+			}
+		}
+	}
+
+	return result
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("You need to specify a file!")
+	}
+
+	filePath := os.Args[1]
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatalf("Failed to open %s!\n", filePath)
+
+	}
+
+	lines := readInput(file)
+	fmt.Println("Part1:", part1(lines))
+	fmt.Println("Part2:", part2(lines))
+}

03/description.txt

@@ -0,0 +1,64 @@
+--- Day 3: Gear Ratios ---
+
+You and the Elf eventually reach a gondola lift station; he says the gondola lift will take you up to the water source, but this is as far as he can bring you. You go inside.
+
+It doesn't take long to find the gondolas, but there seems to be a problem: they're not moving.
+
+"Aaah!"
+
+You turn around to see a slightly-greasy Elf with a wrench and a look of surprise. "Sorry, I wasn't expecting anyone! The gondola lift isn't working right now; it'll still be a while before I can fix it." You offer to help.
+
+The engineer explains that an engine part seems to be missing from the engine, but nobody can figure out which one. If you can add up all the part numbers in the engine schematic, it should be easy to work out which part is missing.
+
+The engine schematic (your puzzle input) consists of a visual representation of the engine. There are lots of numbers and symbols you don't really understand, but apparently any number adjacent to a symbol, even diagonally, is a "part number" and should be included in your sum. (Periods (.) do not count as a symbol.)
+
+Here is an example engine schematic:
+
+467..114..
+...*......
+..35..633.
+......#...
+617*......
+.....+.58.
+..592.....
+......755.
+...$.*....
+.664.598..
+
+In this schematic, two numbers are not part numbers because they are not adjacent to a symbol: 114 (top right) and 58 (middle right). Every other number is adjacent to a symbol and so is a part number; their sum is 4361.
+
+Of course, the actual engine schematic is much larger. What is the sum of all of the part numbers in the engine schematic?
+
+Your puzzle answer was 532445.
+--- Part Two ---
+
+The engineer finds the missing part and installs it in the engine! As the engine springs to life, you jump in the closest gondola, finally ready to ascend to the water source.
+
+You don't seem to be going very fast, though. Maybe something is still wrong? Fortunately, the gondola has a phone labeled "help", so you pick it up and the engineer answers.
+
+Before you can explain the situation, she suggests that you look out the window. There stands the engineer, holding a phone in one hand and waving with the other. You're going so slowly that you haven't even left the station. You exit the gondola.
+
+The missing part wasn't the only issue - one of the gears in the engine is wrong. A gear is any * symbol that is adjacent to exactly two part numbers. Its gear ratio is the result of multiplying those two numbers together.
+
+This time, you need to find the gear ratio of every gear and add them all up so that the engineer can figure out which gear needs to be replaced.
+
+Consider the same engine schematic again:
+
+467..114..
+...*......
+..35..633.
+......#...
+617*......
+.....+.58.
+..592.....
+......755.
+...$.*....
+.664.598..
+
+In this schematic, there are two gears. The first is in the top left; it has part numbers 467 and 35, so its gear ratio is 16345. The second gear is in the lower right; its gear ratio is 451490. (The * adjacent to 617 is not a gear because it is only adjacent to one part number.) Adding up all of the gear ratios produces 467835.
+
+What is the sum of all of the gear ratios in your engine schematic?
+
+Your puzzle answer was 79842967.
+
+Both parts of this puzzle are complete! They provide two gold stars: **

03/input

@@ -0,0 +1,140 @@
+311...672...34...391.....591......828.......................738....................223....803..472..................................714.840.
+.......*...........*.....*...........*........631%...703.......*..12....652.................*.$............368.769*148.................*....
+....411...........2....837.121........511.745...........*.48.422.@.........@.............311........887......*................457........595
+........*328...............&..........................144.*...................138............48.......*......682.........@...*.......777....
+.....144.....+........170...................207............813..../.&....139..*.....346........*..147..143.+.....78....536..79........*.....
+...........828...559.................181...%..........613.......10...928...*...993.+.........758.*.........471...#../...............573.....
+....................*164...132..........*........=.......*.................47.........186.........313..............411......................
+...............342............+..823.....533....519.....899...310................@........325...........15....................407.....#.....
+515......916......*.@...........*.............................*......961.........827......*.......=.........567....=238...874*.......420....
+...=.......*...207...882......719....455.973...................369...*.....*913........978...%..720..........-..............................
+........306................................................182.....534......................229........744.........+.....=..........918.....
+303...........745...........361..............223..243.129.....=.................830.....%.................%......493....106............&....
+.................*209..17.........494.910................*90....496.....709......&....896...................................................
+....%..562............*.....@...........*..528.......321...........*673......................887..%231...............700..............116...
+.988..=....944...596........806...24..519./..........*......../...............146...........*...................554..*......................
+..........$.......................................822...621..771..151.504.......*.628*343..34...+.&..............*..329.303..641..678..+....
+........................361.....347*524..538...........*.........*.....-......790.............933..724......699...........*....*........262.
+.716..517...+..........*................*......955$..544.....238..593.....399.......#..=...................*...........241.....930..........
+...%.+.......744....550..........#131....964.............234..*.............*.....856..809..450....%....332.....419..................389....
+........264...............798......................816....%....228.......501..224........../.......645.............*499.....*.......*.......
+.......*.......939........*.....@..............795*..............................*........................789................907.....647....
+.....612..........*.612..291..592........#.................567...................391.........................*....387............64.........
+................24.....*.................814......=........$......./....346................444............833....*..........845...*.........
+...........303.........605..326.....108.......%..56..842=.....*....387...*..478-..272=....*..........#........778.....299=..@...722.........
+......484=..=.....753..........$......+.....449...............559.......144.............695.........675..................................253
+...-...............*.........*................................................................987.......200......*......445.......124...*...
+....825............603....544.634........................432...=875...738...............731..*.............&..488.363..*.....663.........876
+........755.................................#............-............/.............*....*....470..314.145..............277...@.....234-....
+....323.........221..............892...284..473.....44......342.622.........707....413...984..........*....../..............................
+..............$....*..............*...&........................*.......351%...*.............................226..........155....973+........
+...............177.991..........268.............532=......./.....277........183......*935.........917....*........825.....-.................
+.....+.%................#...413........304...............384....*.................748........./....*...955.......#...........885.970........
+...44...627..........368.../...........=.........................314..293...................102..108............................*...........
+......=.........................=........733..433...128..............*.......889...........................661.........-358...$....281......
+.....35..........$...........834.../699...../.-......................461.......-........*...................*..................374....=.#412
+............763..201..$............................392........341........96......723.340.........327.736...1..$897.....471..................
+.....*512..*.........221.............125$....257.....@.....................*.277.*................*...*................................@....
+..301......694..............54.............../.........611...............596.../..100.......164.801....596..490....&361.........415....412..
+..................243...927*.........29*293........645*.......862*2...........................=............*.....................*..$.......
+............$......&.........655.906...........500....................125.613..844.........@......435......984....725-..531.....711..79.....
+...817...450.....................*........431...%........................*..........957.....739..*.....................*....................
+.....#........237......122.66.942............*.........548..................506.435...............73.883............644...101...............
+.863.............*......&..*..................98..283........532......750..............*........#.......+....594*...........................
+....*.........451.........623.....*....*...........&............%..50*.......44.....123......951.................62.943......365...995......
+.639..............827.265......132..354.127...........350....................*..........................11..........*....%...*..............
+........41..#175....@...*..*.....................+......*..247.353...#.....44.....912-......757...............144..481.693.271.........993..
+.........*.............993.707...857*...........375.....90...@...*..386.......403.............*..................*..............208....=....
+.......343.437....391..........&.....117....637.....345.........43.......*662..@...........908.........956.......908.............&..........
+389.............&...........670.............$...42.....*...=..........564................................%...............+..................
+...*............435....*.............913..............574..149.......................962....................953...77..641....514............
+....448.....783.....892..381.....593.*.........................403*149................%..863*954....373-..+........*...........*.+...663....
+906........................#......*...922.........950......................993...3.........................379....450.......877..804.#......
+...............768.......*......-.198.........160*............820......382...*......169.........*555..257...................................
+260..............*.....68.....281.......871...................*...980......875.......*.......169........*.............531......@............
+....*......@.....587...................#......48..251..316@...848..................303................931..132..............790.............
+.....205...572................696........&.....@.....@............709..611.............=.......270........*....165......783.......790.......
+......................965.........709..826....................882*......%..775.........391....*......985.5........*179.....*47.......&......
+.....451............@................#..................804..................$..161...........837..............*................$904....176.
+720.................70..........899.....868..............=.......357.252.......*..................707.......898.139.....704............*....
+....................................307*....510..................*.....*.......17..501.............*................@....*..........855.....
+.............745............451................*..689..980..@670.594.716..........*.................565......595..622.....793...............
+.....890......$...73...422...*...977&.......324..%.......@................29.......945....*.............298-..................#.........#642
+........*........*....%......................................$645......-...*...150.....434.259..609*560....../............266..524..../.....
+.....203..........133.....596.619.................*...............676.107..811...*...........................115...........*.........178....
+............................=..*...............157.682.......262..*............196......$..........707................14..386...............
+.........871............605....721...........................*...867.................685..866.......*.............602...............628.....
+......#.....*....413.......@.......380....872................372.......277......277.........*.......166...........@..........656....*....748
+.....841..664.......*.422............................945...........%............*.........959.863.........187........299.......*.....887....
+.708..............311....+..296*497.....751...639....*..........269..........875....%.........................-.................36..........
+.........834..............................@...........708...........................87....298..*471.....$.....463...........................
+............+...739..........701........................................779................=.........265..642...............................
+......504..........*...............871*314....127..36..639.196..48..................96......../785.........*..854=.....607=...542...........
+...73............254.591.........................*..$.....*......*.........35......*...@................150...................-........340..
+........224............/....*214...=..........949..............455.........*.......377.88....................823......582.............*.....
+.......*.......643.......901........191..267.......293...................194..266.................987.......*........&....+.........545.....
+....604...583.....*............*742........*.........*........$..................*..365............*....=...880.55......540.520#............
+............*..272.....843..201.....*....&.128..+....433.......563......281*77.540.+.......979&..134....514.......*..............46.........
+...966.....67.......................19.934......224..........#....................................................693............*.....525..
+....*.........188.....904......*..............................210....*958.........811...............574....965................288..20.$.....
+..213.........*...137*.......325.....628..................406......34..............*.......406...$.*.........*.........867..........*.......
+...........810............................*.....926.........*..............372.....372.....*...266.716........985......*.............1......
+...............399*126.....*.......*...379..729.+........245.........893....-..866.....101.299..........8.544........784....................
+954......................63.501.529........-.......695/.................................*..........320....................211.55...533......
+............457..........................=.......................375#..........961*......720......*...............542........*.....+...327..
+........396...*.476.774.680.189@.438......669............936.......................195.......405.926.213.....254.....*.................*....
+...-.......-.......*.....&...........$........22....732.*.......$121.200...............-.......*........*.............522.825..77...........
+....272..............#............925.....378*......&....53.............*....605.....329.116..501..=.765......537.680......*..*.........#...
+817........109....209...........................690...................573...&............/........48...........*.....*..169...581.......537.
+...=..747.............171.70.........990........*..............529.............482.....................383......531.53.............#211.....
+......*.....470........*...*.812.664.=.......141.....82...888...*.................@.312....9*860...........529............./...952..........
+.....906...*....810...966....*.....*.....................*.......616........327-.....*...............................80.655.................
+323......459......@.........185.....894..891..........254.................................938.........262........602*.......................
+.............110.........................$......*55..........155..................248*600.....66........*...............*......75..880......
+.....459...........928...............................*900.....@.....27............................526....434.402.....840.816.......*........
+......*........241....*...70.465...668....110=....905...........252..*..............%..........74.............*.................817...290...
+.540...224........*.42......*........*.................705.......*..128...&.758=.512...884.....*..648*.......259.......486.627.......*......
+....*..........467................462..321....296*211.*........283......488...........%......796......774.............%.......+.200.87......
+...663..............$961..579...........................*...................189..........71................420..57...............*..........
+...........617.645...........*........700..886...806.581.610.....132.379.......$......+....-..941$.....................504....589........528
+......377.......+.....290...221..768.....*....&....&................*.................556..............132.............*....................
+......................+.............*152.448............903.....339.....=.......709............991.......*.............865..................
+....-.....$717.............552................40..458....*.....*......365.......-......762.732...*.....690.266.....222............122.......
+.414...........496...+.712..*...=....785.........*.......79...884.991................/....*.....844..-........@....*...782...........*627...
+.......$........%..560..*...873..739..#........368.991......*.....*.....27..........951..............864.........206...*...878..............
+.....231..995...........865................602......*....379.609.935...+......643................952.....@...........884...*................
+.............$....726........360..........=.................................................*990.+........959............932................
+.....................+.508.....=...194.......*30........./...........487......171...243..709........495.........995.464.......997...........
+......292..............$.............*....253.........*.554...........*......../......................*.........*....%......*....*582.446...
+...........802.....237.....*32...286.259............132.....236......683.....&.......................705...$855.37.....=...476.........*....
+.....418=.............*.664........*..........*11............$.....=.....70.380....138.....416.609..................452........43...156..260
+....................20..........512........303.....-................491...*.......*.........*..&..........&962..........*......#........-...
+426.646....833...........821....................348.......537...668........92.....295.....620...................147=.753....................
+......*.....*..................210.681...................$..........937.......350......................533............................+.....
+.65...22..656...#........*44...*.......178*.........446.........655..............*592.....952-.....680..*...........=..305#............704..
+...*.............422..835......126.........552.......*....543..........-....444.......995.........=.....771........480.........782..........
+............28............983$...........5............953.&.......216..749....=..........-....................232...........................
+.....................878................*.........426...............*.........................$........792%..*....898......264...39.........
+...480.....674..149+...................740......#....*251..920.......552......................713...........639.......917.........*.........
+...+........+...................$951..........*..968.......*............................................750.......479............770.959....
+...............424..54*489..+...........14..355...........782...50................900.770..........639.....&.942.....*39.....477........+...
+....888.....................412................................*...%123...579...../....&.....315.....#..........*..............*..66........
+......*..........................793..402.......*807...854@...115........................=...*...204.......208..928..........121............
+...........880=.818......982......*......*...923.......................................809.962...*.........&................................
+...957*511.........*436..@......704.......................-......../....84/...369.496..........917.....................464..................
+............................812.........785*...............848..506..................*116................=..#...............................
+..........694..257..876.....................15.........176.............................................593...168...914.230-.200.........500.
+...427...&.....*..........................................*.............=...%....233..616&....299*.................-....................=...
+......&......598............571/....60.........897.......911....34....106...713.@.............................933..........288..............
+..314...............563...&...........*...........*............*......................198........................*............*591....246...
+....*......274.875.....+.114...........105.763..319...................*730.....158.....................487.......505........................
+.439..........*......................*........*.......595.190.173..653............*...882.812.....*230..-............522....=.......192.....
+................554...825...845...797.572..814.......*.......*............*....167.......*.....581...................-.......330.......#....
+.......82......*......$....#.........................318...............326.924......880....288..........*.....44.....................+......
+.....-...-....526.........................=981...........959....................*.............*......915.116.*....$...=..............577....
+..130..............................@330..............414.*....679........999.344.611.......432..................690....502..................
+.............476...#.........................................&.............%...........303.....731.........681..............................
+....@791....*....152....397....*.....975............904................225...............*.......$........&.....169.207.....................
+..........995...........&...558.857.......141..803.%....-........199.....*......573..63..315................*...........519.................
+......................................158*....*........737.........%....399....*..................#47....100................574...#333......
+..........56............822..................665............................563..383........................................................

04/code.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+type Card struct {
+	id      int
+	winning []int
+	owned   []int
+}
+
+func readNumbers(part string) []int {
+	var numbers []int
+	numberParts := strings.Split(part, " ")
+	if len(numberParts) == 0 {
+		log.Fatalf("Can't split numbers: %s", part)
+	}
+
+	for i := range numberParts {
+		if numberParts[i] == "" {
+			continue
+		}
+
+		var number int
+		n, err := fmt.Sscanf(numberParts[i], "%d", &number)
+		if n != 1 || err != nil {
+			log.Fatalf("Can't read number: %s\n%s", numberParts[i], err)
+		}
+
+		numbers = append(numbers, number)
+	}
+
+	return numbers
+}
+
+func readInput(file *os.File) []Card {
+	scanner := bufio.NewScanner(file)
+	var cards []Card
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			break
+		}
+
+		var current Card
+		n, err := fmt.Sscanf(line, "Card %d:", &current.id)
+		if n != 1 || err != nil {
+			log.Fatalf("Failed to read card id: %s\n%s", line, err)
+		}
+
+		parts := strings.Split(line, ":")
+		if len(parts) != 2 {
+			log.Fatalf("Can't split card: %s", line)
+		}
+
+		numberParts := strings.Split(parts[1], "|")
+		if len(parts) != 2 {
+			log.Fatalf("Can't split tables: %s", line)
+		}
+
+		current.winning = append(current.winning, readNumbers(numberParts[0])...)
+		current.owned = append(current.owned, readNumbers(numberParts[1])...)
+		cards = append(cards, current)
+	}
+
+	return cards
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("You need to specify a file!")
+	}
+
+	filePath := os.Args[1]
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatalf("Failed to open %s!\n", filePath)
+
+	}
+
+	cards := readInput(file)
+	fmt.Println(cards)
+}