advent-of-code 2025.5.0

Solutions to Advent of Code
Documentation 
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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244

use crate::input::Input;

pub fn solve(input: &Input) -> Result<u64, String> {
    let mut cuboids = input
        .text
        .lines()
        .map(Cuboid::parse)
        .collect::<Option<Vec<_>>>()
        .ok_or("Invalid input")?;

    if input.is_part_one() {
        cuboids.retain(|c| {
            !(c.max_corner.x < -50
                || c.min_corner.x > 50
                || c.max_corner.y < -50
                || c.min_corner.y > 50
                || c.max_corner.z < -50
                || c.min_corner.z > 50)
        });
        for c in cuboids.iter_mut() {
            c.min_corner.x = c.min_corner.x.clamp(-50, 50);
            c.max_corner.x = c.max_corner.x.clamp(-50, 50);
            c.min_corner.y = c.min_corner.y.clamp(-50, 50);
            c.max_corner.y = c.max_corner.y.clamp(-50, 50);
            c.min_corner.z = c.min_corner.z.clamp(-50, 50);
            c.max_corner.z = c.max_corner.z.clamp(-50, 50);
        }
    }

    Ok(Cuboid::combine_and_count_enclosed_cubes(&cuboids))
}

#[derive(Clone, Default)]
struct Coordinate {
    x: i32,
    y: i32,
    z: i32,
}

#[derive(Clone)]
struct Cuboid {
    on: bool,
    min_corner: Coordinate,
    max_corner: Coordinate,
}

impl Cuboid {
    fn parse(text: &str) -> Option<Self> {
        let on = text.starts_with("on");
        let range_parts = text.split(&['=', '.', ','][..]).collect::<Vec<_>>();
        if range_parts.len() != 12 {
            return None;
        }
        let x_min = range_parts[1].parse::<i32>().ok()?;
        let x_max = range_parts[3].parse::<i32>().ok()?;
        let y_min = range_parts[5].parse::<i32>().ok()?;
        let y_max = range_parts[7].parse::<i32>().ok()?;
        let z_min = range_parts[9].parse::<i32>().ok()?;
        let z_max = range_parts[11].parse::<i32>().ok()?;
        Some(Self {
            on,
            min_corner: Coordinate {
                x: x_min,
                y: y_min,
                z: z_min,
            },
            max_corner: Coordinate {
                x: x_max,
                y: y_max,
                z: z_max,
            },
        })
    }

    fn intersect_with(&self, other: &Self) -> Option<Self> {
        let x_intersection = Self::intersect_intervals(
            (self.min_corner.x, self.max_corner.x),
            (other.min_corner.x, other.max_corner.x),
        )?;
        let y_intersection = Self::intersect_intervals(
            (self.min_corner.y, self.max_corner.y),
            (other.min_corner.y, other.max_corner.y),
        )?;
        let z_intersection = Self::intersect_intervals(
            (self.min_corner.z, self.max_corner.z),
            (other.min_corner.z, other.max_corner.z),
        )?;

        Some(Self {
            // Matching on (self.on, other.on):
            // (on, on): Avoid double counting (as other whole cuboid will be added).
            // (on, off): Turning off a turned on cuboid.
            // (off, on): Turning on a turned off cuboid.
            // (off, off): Turning off a turned off correction cuboid.
            on: !self.on,
            min_corner: Coordinate {
                x: x_intersection.0,
                y: y_intersection.0,
                z: z_intersection.0,
            },
            max_corner: Coordinate {
                x: x_intersection.1,
                y: y_intersection.1,
                z: z_intersection.1,
            },
        })
    }

    fn intersect_intervals(interval_a: (i32, i32), interval_b: (i32, i32)) -> Option<(i32, i32)> {
        if interval_b.0 > interval_a.1 || interval_a.0 > interval_b.1 {
            None
        } else {
            let intersection_start = std::cmp::max(interval_a.0, interval_b.0);
            let intersection_end = std::cmp::min(interval_a.1, interval_b.1);
            Some((intersection_start, intersection_end))
        }
    }

    const fn enclosed_cubes(&self) -> u64 {
        (1 + self.max_corner.x - self.min_corner.x) as u64
            * (1 + self.max_corner.y - self.min_corner.y) as u64
            * (1 + self.max_corner.z - self.min_corner.z) as u64
    }

    fn combine_and_count_enclosed_cubes(cuboids: &[Self]) -> u64 {
        let mut combined = Vec::with_capacity(cuboids.len() / 2);
        for cuboid in cuboids {
            combined.append(
                &mut combined
                    .iter()
                    .filter_map(|already_combined: &Self| already_combined.intersect_with(cuboid))
                    .collect::<Vec<_>>(),
            );
            if cuboid.on {
                combined.push(cuboid.clone());
            }
        }

        combined
            .iter()
            .map(|cuboid| {
                let multiplier = if cuboid.on { 1 } else { -1 };
                multiplier * (cuboid.enclosed_cubes() as i64)
            })
            .sum::<i64>() as u64
    }
}

#[test]
pub fn tests() {
    let example = "on x=10..12,y=10..12,z=10..12
on x=11..13,y=11..13,z=11..13
off x=9..11,y=9..11,z=9..11
on x=10..10,y=10..10,z=10..10";
    test_part_one!(example => 39);
    let example = "on x=-20..26,y=-36..17,z=-47..7
on x=-20..33,y=-21..23,z=-26..28
on x=-22..28,y=-29..23,z=-38..16
on x=-46..7,y=-6..46,z=-50..-1
on x=-49..1,y=-3..46,z=-24..28
on x=2..47,y=-22..22,z=-23..27
on x=-27..23,y=-28..26,z=-21..29
on x=-39..5,y=-6..47,z=-3..44
on x=-30..21,y=-8..43,z=-13..34
on x=-22..26,y=-27..20,z=-29..19
off x=-48..-32,y=26..41,z=-47..-37
on x=-12..35,y=6..50,z=-50..-2
off x=-48..-32,y=-32..-16,z=-15..-5
on x=-18..26,y=-33..15,z=-7..46
off x=-40..-22,y=-38..-28,z=23..41
on x=-16..35,y=-41..10,z=-47..6
off x=-32..-23,y=11..30,z=-14..3
on x=-49..-5,y=-3..45,z=-29..18
off x=18..30,y=-20..-8,z=-3..13
on x=-41..9,y=-7..43,z=-33..15
on x=-54112..-39298,y=-85059..-49293,z=-27449..7877
on x=967..23432,y=45373..81175,z=27513..53682";
    test_part_one!(example => 590_784);
    let example = "on x=-5..47,y=-31..22,z=-19..33
on x=-44..5,y=-27..21,z=-14..35
on x=-49..-1,y=-11..42,z=-10..38
on x=-20..34,y=-40..6,z=-44..1
off x=26..39,y=40..50,z=-2..11
on x=-41..5,y=-41..6,z=-36..8
off x=-43..-33,y=-45..-28,z=7..25
on x=-33..15,y=-32..19,z=-34..11
off x=35..47,y=-46..-34,z=-11..5
on x=-14..36,y=-6..44,z=-16..29
on x=-57795..-6158,y=29564..72030,z=20435..90618
on x=36731..105352,y=-21140..28532,z=16094..90401
on x=30999..107136,y=-53464..15513,z=8553..71215
on x=13528..83982,y=-99403..-27377,z=-24141..23996
on x=-72682..-12347,y=18159..111354,z=7391..80950
on x=-1060..80757,y=-65301..-20884,z=-103788..-16709
on x=-83015..-9461,y=-72160..-8347,z=-81239..-26856
on x=-52752..22273,y=-49450..9096,z=54442..119054
on x=-29982..40483,y=-108474..-28371,z=-24328..38471
on x=-4958..62750,y=40422..118853,z=-7672..65583
on x=55694..108686,y=-43367..46958,z=-26781..48729
on x=-98497..-18186,y=-63569..3412,z=1232..88485
on x=-726..56291,y=-62629..13224,z=18033..85226
on x=-110886..-34664,y=-81338..-8658,z=8914..63723
on x=-55829..24974,y=-16897..54165,z=-121762..-28058
on x=-65152..-11147,y=22489..91432,z=-58782..1780
on x=-120100..-32970,y=-46592..27473,z=-11695..61039
on x=-18631..37533,y=-124565..-50804,z=-35667..28308
on x=-57817..18248,y=49321..117703,z=5745..55881
on x=14781..98692,y=-1341..70827,z=15753..70151
on x=-34419..55919,y=-19626..40991,z=39015..114138
on x=-60785..11593,y=-56135..2999,z=-95368..-26915
on x=-32178..58085,y=17647..101866,z=-91405..-8878
on x=-53655..12091,y=50097..105568,z=-75335..-4862
on x=-111166..-40997,y=-71714..2688,z=5609..50954
on x=-16602..70118,y=-98693..-44401,z=5197..76897
on x=16383..101554,y=4615..83635,z=-44907..18747
off x=-95822..-15171,y=-19987..48940,z=10804..104439
on x=-89813..-14614,y=16069..88491,z=-3297..45228
on x=41075..99376,y=-20427..49978,z=-52012..13762
on x=-21330..50085,y=-17944..62733,z=-112280..-30197
on x=-16478..35915,y=36008..118594,z=-7885..47086
off x=-98156..-27851,y=-49952..43171,z=-99005..-8456
off x=2032..69770,y=-71013..4824,z=7471..94418
on x=43670..120875,y=-42068..12382,z=-24787..38892
off x=37514..111226,y=-45862..25743,z=-16714..54663
off x=25699..97951,y=-30668..59918,z=-15349..69697
off x=-44271..17935,y=-9516..60759,z=49131..112598
on x=-61695..-5813,y=40978..94975,z=8655..80240
off x=-101086..-9439,y=-7088..67543,z=33935..83858
off x=18020..114017,y=-48931..32606,z=21474..89843
off x=-77139..10506,y=-89994..-18797,z=-80..59318
off x=8476..79288,y=-75520..11602,z=-96624..-24783
on x=-47488..-1262,y=24338..100707,z=16292..72967
off x=-84341..13987,y=2429..92914,z=-90671..-1318
off x=-37810..49457,y=-71013..-7894,z=-105357..-13188
off x=-27365..46395,y=31009..98017,z=15428..76570
off x=-70369..-16548,y=22648..78696,z=-1892..86821
on x=-53470..21291,y=-120233..-33476,z=-44150..38147
off x=-93533..-4276,y=-16170..68771,z=-104985..-24507";
    test_part_two!(example => 2_758_514_936_282_235);

    let real_input = include_str!("day22_input.txt");
    test_part_one!(real_input => 576_028);
    test_part_two!(real_input => 1_387_966_280_636_636);
}