1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
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
}
|
