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Diffstat (limited to 'aoc2023/day2/src')
-rw-r--r-- | aoc2023/day2/src/main.rs | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/aoc2023/day2/src/main.rs b/aoc2023/day2/src/main.rs new file mode 100644 index 0000000..e42b9c5 --- /dev/null +++ b/aoc2023/day2/src/main.rs @@ -0,0 +1,158 @@ +/* +--- 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? + +--- 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? + + */ + +use std::cmp::max; +use std::fs; + +fn main() { + let input = fs::read_to_string("input").unwrap(); + + let max_red = 12; + let max_green = 13; + let max_blue = 14; + + let games:Vec<(i32, Vec<(i32, i32, i32)>)> = input.lines() + .map(construct_game) + .collect(); + + let total = games.iter().filter_map(|game| { + for cubeset in game.1.clone() { + if cubeset.0 > max_red || cubeset.1 > max_green || cubeset.2 > max_blue { + println!("Game {} is invalid", game.0); + return None + } + } + println!("Game {} is valid", game.0); + Some(game.0) + }).reduce(|acc, game| acc + game).unwrap(); + + println!("Part one answer: {total}"); + + let power_total = games.iter() + .map(game_power) + .reduce(|acc, e| acc + e) + .unwrap(); + + println!("Part two answer: {power_total}"); +} + +fn construct_game(line: &str) -> (i32, Vec<(i32, i32, i32)>) { + let t = line.split_once(":").unwrap(); + + let n = t.0.trim_start_matches("Game ") + .parse::<i32>().expect("game number is valid"); + + let cubesets = t.1.split(";") + .map(parse_cubeset) + .collect(); + + (n, cubesets) +} + +fn parse_cubeset(set: &str) -> (i32, i32, i32) { + let mut red = 0; + let mut green = 0; + let mut blue = 0; + + set.split(",") + .for_each(|cubes| { + if cubes.contains("red") { + red += cubes.trim().split_once(" ").unwrap().0 + .parse::<i32>().expect("can parse red cubes"); + } else if cubes.contains("green") { + green += cubes.trim().split_once(" ").unwrap().0 + .parse::<i32>().expect("can parse green cubes"); + } else if cubes.contains("blue") { + blue += cubes.trim().split_once(" ").unwrap().0 + .parse::<i32>().expect("can parse blue cubes"); + } + }); + + (red, green, blue) +} + +fn game_power(game:&(i32, Vec<(i32, i32, i32)>)) -> i32 { + let mut red = 0; + let mut green = 0; + let mut blue = 0; + + for cubeset in game.1.clone() { + red = max(cubeset.0, red); + green = max(cubeset.1, green); + blue = max(cubeset.2, blue); + } + + red * green * blue +} \ No newline at end of file |