summaryrefslogtreecommitdiff
path: root/2020/src/bin/day_11.rs
blob: 82bb2824903cd40ef0d028b7e5c9cad7d2d8329a (plain)
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
use bevy::prelude::*;
use std::fs::File;
use std::io::{BufRead, BufReader};

fn main() {
    App::build()
        .add_resource(WindowDescriptor {
            title: "Advent of Code".to_string(),
            width: 1920,
            height: 1080,
            ..Default::default()
        })
        .add_event::<AdjacentStableEvent>()
        .add_event::<LineOfSightStableEvent>()
        .add_resource(ClearColor(Color::rgb(0., 0., 0.)))
        .add_startup_system(setup_camera.system())
        .add_startup_system(read_input_file.system())
        .add_system(iterate_adjacent_seats.system())
        .add_system(iterate_line_of_sight_seats.system())
        .add_system(report_adjacent_done.system())
        .add_system(report_line_of_sight_done.system())
        .add_plugins(DefaultPlugins)
        .run();
}

fn setup_camera(mut commands: Commands) {
    commands.spawn(Camera2dComponents::default());
}

#[derive(PartialEq, Eq, Clone, Copy)]
struct Position {
    x: i32,
    y: i32,
}
impl Position {
    fn distance(&self, other: &Position) -> i32 {
        (self.x - other.x).abs().max((self.y - other.y).abs())
    }
}
impl std::ops::Add<&Position> for Position {
    type Output = Position;
    fn add(self, other: &Position) -> Self::Output {
        Position {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

struct AdjacentSeat {
    occupied: bool,
}
struct LineOfSightSeat {
    occupied: bool,
}

struct AdjacentStableEvent;
struct LineOfSightStableEvent;

#[derive(Default)]
struct Bounds {
    min_x: i32,
    max_x: i32,
    min_y: i32,
    max_y: i32,
}

fn read_input_file(mut commands: Commands) {
    let f = File::open("./inputs/day_11.txt").unwrap();
    let mut bounds = Bounds::default();

    for (y, line) in BufReader::new(f).lines().enumerate() {
        let line = line.unwrap();
        let line = line.trim();
        for (x, c) in line.chars().enumerate() {
            if c == 'L' {
                commands.spawn((
                    Position {
                        x: x as i32,
                        y: y as i32,
                    },
                    AdjacentSeat { occupied: false },
                    LineOfSightSeat { occupied: false },
                ));
            }
            bounds.max_x = x as i32;
        }

        bounds.max_y = y as i32;
    }
    commands.insert_resource(bounds);
}

fn iterate_adjacent_seats(
    mut commands: Commands,
    mut stable_events: ResMut<Events<AdjacentStableEvent>>,
    seats: Query<(Entity, &Position, &AdjacentSeat)>,
) {
    let mut changes: Vec<(Entity, AdjacentSeat)> = Vec::new();
    for (entity, position, seat) in seats.iter() {
        let surrounding_count = seats
            .iter()
            .filter(|(_, other_position, other_seat)| {
                other_seat.occupied && position.distance(other_position) == 1
            })
            .count();
        let change = if !seat.occupied && surrounding_count == 0 {
            Some(true)
        } else if seat.occupied && surrounding_count >= 4 {
            Some(false)
        } else {
            None
        };
        if let Some(occupied) = change {
            changes.push((entity, AdjacentSeat { occupied }));
        }
    }
    if changes.is_empty() {
        stable_events.send(AdjacentStableEvent);
    }

    for (entity, seat) in changes {
        commands.insert_one(entity, seat);
    }
}

fn iterate_line_of_sight_seats(
    mut commands: Commands,
    mut stable_events: ResMut<Events<LineOfSightStableEvent>>,
    bounds: Res<Bounds>,
    seats: Query<(Entity, &Position, &LineOfSightSeat)>,
) {
    let dir_vectors = [
        Position { x: -1, y: 0 },
        Position { x: -1, y: -1 },
        Position { x: 0, y: -1 },
        Position { x: 1, y: -1 },
        Position { x: 1, y: 0 },
        Position { x: 1, y: 1 },
        Position { x: 0, y: 1 },
        Position { x: -1, y: 1 },
    ];

    let mut changes: Vec<(Entity, LineOfSightSeat)> = Vec::new();
    for (entity, position, seat) in seats.iter() {
        let mut surrounding_count = 0;
        for vec in dir_vectors.iter() {
            let mut check = position.clone();
            while check.x >= bounds.min_x
                && check.x <= bounds.max_x
                && check.y >= bounds.min_y
                && check.y <= bounds.max_y
            {
                check = check + vec;
                if let Some((_, _, other_seat)) =
                    seats.iter().find(|(_, other_pos, _)| other_pos == &&check)
                {
                    if other_seat.occupied {
                        surrounding_count += 1;
                    }
                    break;
                }
            }
        }

        let change = if !seat.occupied && surrounding_count == 0 {
            Some(true)
        } else if seat.occupied && surrounding_count >= 5 {
            Some(false)
        } else {
            None
        };
        if let Some(occupied) = change {
            changes.push((entity, LineOfSightSeat { occupied }));
        }
    }
    if changes.is_empty() {
        stable_events.send(LineOfSightStableEvent);
    }

    for (entity, seat) in changes {
        commands.insert_one(entity, seat);
    }
}

fn report_adjacent_done(
    stable_events: Res<Events<AdjacentStableEvent>>,
    mut stable_event_reader: Local<EventReader<AdjacentStableEvent>>,
    seats: Query<&AdjacentSeat>,
) {
    for _ in stable_event_reader.iter(&stable_events) {
        let occupied = seats.iter().filter(|s| s.occupied).count();
        println!("{} seats end up occupied in the adjacent model", occupied);
    }
}

fn report_line_of_sight_done(
    stable_events: Res<Events<LineOfSightStableEvent>>,
    mut stable_event_reader: Local<EventReader<LineOfSightStableEvent>>,
    seats: Query<&LineOfSightSeat>,
) {
    for _ in stable_event_reader.iter(&stable_events) {
        let occupied = seats.iter().filter(|s| s.occupied).count();
        println!(
            "{} seats end up occupied in the line of sight model",
            occupied
        );
    }
}