Day 10

2 files changed, 399 insertions, 0 deletions

diff --git a/input/day10.txt b/input/day10.txt
new file mode 100644
index 0000000..40bc918
--- /dev/null
+++ b/input/day10.txt
@@ -0,0 +1,231 @@
+bot 76 gives low to bot 191 and high to bot 21
+bot 193 gives low to bot 118 and high to bot 145
+bot 173 gives low to bot 91 and high to bot 36
+value 23 goes to bot 68
+bot 129 gives low to bot 124 and high to bot 155
+bot 58 gives low to output 2 and high to bot 51
+bot 97 gives low to bot 205 and high to bot 156
+bot 95 gives low to bot 21 and high to bot 204
+bot 56 gives low to bot 202 and high to bot 97
+bot 181 gives low to bot 144 and high to bot 101
+bot 20 gives low to bot 42 and high to bot 23
+bot 122 gives low to bot 190 and high to bot 50
+bot 202 gives low to bot 103 and high to bot 205
+bot 169 gives low to bot 125 and high to bot 208
+bot 91 gives low to bot 58 and high to bot 17
+bot 10 gives low to bot 127 and high to bot 1
+bot 119 gives low to bot 50 and high to bot 149
+bot 194 gives low to bot 38 and high to bot 77
+bot 82 gives low to bot 49 and high to bot 22
+bot 180 gives low to bot 199 and high to bot 71
+bot 191 gives low to bot 146 and high to bot 13
+bot 111 gives low to bot 186 and high to bot 89
+bot 75 gives low to bot 195 and high to bot 117
+bot 17 gives low to bot 51 and high to bot 184
+value 5 goes to bot 209
+bot 139 gives low to bot 81 and high to bot 57
+bot 36 gives low to bot 17 and high to bot 46
+bot 158 gives low to bot 30 and high to bot 6
+bot 40 gives low to bot 160 and high to bot 82
+value 11 goes to bot 175
+value 3 goes to bot 170
+bot 208 gives low to bot 14 and high to bot 104
+bot 113 gives low to output 15 and high to bot 27
+bot 96 gives low to bot 170 and high to bot 110
+bot 9 gives low to bot 102 and high to bot 132
+value 67 goes to bot 129
+bot 35 gives low to bot 24 and high to bot 187
+bot 172 gives low to bot 117 and high to bot 64
+bot 157 gives low to bot 65 and high to bot 136
+bot 179 gives low to bot 178 and high to bot 197
+bot 144 gives low to bot 172 and high to bot 2
+bot 51 gives low to output 8 and high to bot 31
+bot 177 gives low to bot 194 and high to bot 61
+bot 106 gives low to bot 134 and high to bot 52
+bot 148 gives low to bot 86 and high to bot 199
+bot 64 gives low to bot 48 and high to bot 146
+bot 121 gives low to bot 165 and high to bot 116
+bot 146 gives low to bot 9 and high to bot 69
+bot 199 gives low to bot 141 and high to bot 152
+bot 166 gives low to bot 62 and high to bot 201
+bot 102 gives low to bot 151 and high to bot 179
+bot 15 gives low to bot 80 and high to bot 3
+bot 105 gives low to bot 197 and high to bot 86
+bot 2 gives low to bot 64 and high to bot 191
+bot 3 gives low to bot 169 and high to bot 208
+bot 39 gives low to bot 43 and high to bot 98
+bot 196 gives low to bot 66 and high to bot 32
+value 47 goes to bot 142
+bot 110 gives low to bot 29 and high to bot 40
+bot 151 gives low to bot 74 and high to bot 178
+bot 164 gives low to bot 4 and high to bot 93
+bot 61 gives low to bot 77 and high to bot 144
+bot 29 gives low to bot 183 and high to bot 160
+bot 79 gives low to bot 204 and high to bot 37
+bot 188 gives low to output 0 and high to bot 72
+bot 131 gives low to bot 54 and high to bot 38
+bot 59 gives low to output 4 and high to bot 34
+bot 8 gives low to bot 101 and high to bot 7
+bot 189 gives low to bot 46 and high to bot 53
+bot 77 gives low to bot 75 and high to bot 172
+bot 206 gives low to bot 56 and high to bot 107
+bot 114 gives low to bot 188 and high to bot 125
+bot 207 gives low to bot 87 and high to bot 10
+bot 30 gives low to bot 106 and high to bot 11
+bot 167 gives low to bot 45 and high to bot 183
+bot 168 gives low to output 12 and high to bot 58
+bot 142 gives low to bot 68 and high to bot 111
+bot 138 gives low to bot 180 and high to bot 198
+bot 171 gives low to bot 150 and high to bot 35
+bot 5 gives low to bot 39 and high to bot 100
+bot 197 gives low to bot 120 and high to bot 173
+bot 46 gives low to bot 184 and high to bot 128
+bot 137 gives low to bot 0 and high to bot 114
+bot 7 gives low to bot 76 and high to bot 95
+bot 104 gives low to bot 159 and high to bot 203
+bot 103 gives low to bot 5 and high to bot 108
+bot 66 gives low to bot 158 and high to bot 161
+bot 156 gives low to bot 166 and high to bot 201
+bot 178 gives low to bot 130 and high to bot 120
+bot 1 gives low to bot 206 and high to bot 107
+bot 65 gives low to bot 111 and high to bot 143
+bot 150 gives low to bot 25 and high to bot 24
+value 7 goes to bot 135
+bot 48 gives low to bot 182 and high to bot 9
+bot 112 gives low to bot 22 and high to bot 202
+bot 32 gives low to bot 161 and high to bot 42
+bot 12 gives low to bot 61 and high to bot 181
+bot 155 gives low to bot 196 and high to bot 73
+value 73 goes to bot 140
+bot 99 gives low to bot 109 and high to bot 151
+bot 163 gives low to bot 131 and high to bot 194
+bot 98 gives low to bot 174 and high to bot 26
+value 53 goes to bot 4
+bot 204 gives low to bot 18 and high to bot 126
+bot 19 gives low to output 6 and high to bot 113
+bot 190 gives low to bot 7 and high to bot 154
+bot 88 gives low to bot 26 and high to bot 122
+bot 153 gives low to bot 113 and high to bot 33
+bot 49 gives low to bot 193 and high to bot 55
+value 37 goes to bot 150
+bot 53 gives low to bot 128 and high to bot 15
+bot 80 gives low to bot 114 and high to bot 169
+bot 192 gives low to bot 115 and high to bot 138
+bot 132 gives low to bot 179 and high to bot 105
+bot 57 gives low to bot 41 and high to bot 206
+bot 118 gives low to bot 20 and high to bot 162
+bot 37 gives low to bot 126 and high to bot 78
+bot 201 gives low to bot 16 and high to bot 119
+bot 145 gives low to bot 162 and high to bot 39
+bot 62 gives low to bot 88 and high to bot 16
+bot 133 gives low to bot 59 and high to bot 200
+bot 52 gives low to bot 19 and high to bot 153
+bot 28 gives low to bot 200 and high to bot 182
+bot 149 gives low to bot 79 and high to bot 37
+bot 117 gives low to bot 28 and high to bot 48
+bot 4 gives low to bot 171 and high to bot 93
+bot 182 gives low to bot 99 and high to bot 102
+value 2 goes to bot 92
+bot 170 gives low to bot 167 and high to bot 29
+bot 187 gives low to bot 47 and high to bot 63
+bot 72 gives low to output 20 and high to bot 176
+bot 209 gives low to bot 94 and high to bot 30
+bot 26 gives low to bot 8 and high to bot 190
+bot 162 gives low to bot 23 and high to bot 43
+bot 16 gives low to bot 122 and high to bot 119
+bot 200 gives low to bot 34 and high to bot 99
+bot 68 gives low to bot 175 and high to bot 186
+bot 85 gives low to bot 82 and high to bot 112
+value 61 goes to bot 45
+bot 38 gives low to bot 123 and high to bot 75
+bot 108 gives low to bot 100 and high to bot 62
+bot 34 gives low to output 17 and high to bot 109
+bot 90 gives low to bot 44 and high to bot 193
+bot 94 gives low to bot 135 and high to bot 106
+value 19 goes to bot 124
+bot 184 gives low to bot 31 and high to bot 137
+bot 134 gives low to output 3 and high to bot 19
+bot 63 gives low to bot 207 and high to bot 10
+bot 24 gives low to bot 157 and high to bot 47
+bot 185 gives low to bot 147 and high to bot 81
+bot 18 gives low to bot 84 and high to bot 192
+bot 130 gives low to output 14 and high to bot 168
+bot 78 gives low to bot 138 and high to bot 198
+bot 69 gives low to bot 132 and high to bot 60
+bot 161 gives low to bot 6 and high to bot 163
+bot 176 gives low to output 5 and high to bot 159
+bot 55 gives low to bot 145 and high to bot 5
+bot 160 gives low to bot 90 and high to bot 49
+value 71 goes to bot 167
+bot 165 gives low to bot 53 and high to bot 116
+bot 128 gives low to bot 137 and high to bot 80
+bot 67 gives low to bot 140 and high to bot 66
+bot 86 gives low to bot 173 and high to bot 141
+bot 93 gives low to bot 35 and high to bot 187
+bot 175 gives low to bot 96 and high to bot 70
+bot 174 gives low to bot 181 and high to bot 8
+bot 14 gives low to bot 176 and high to bot 104
+bot 13 gives low to bot 69 and high to bot 84
+bot 54 gives low to bot 153 and high to bot 123
+bot 135 gives low to output 10 and high to bot 134
+bot 101 gives low to bot 2 and high to bot 76
+bot 147 gives low to bot 40 and high to bot 85
+bot 205 gives low to bot 108 and high to bot 166
+bot 141 gives low to bot 36 and high to bot 189
+bot 84 gives low to bot 60 and high to bot 115
+bot 115 gives low to bot 148 and high to bot 180
+value 31 goes to bot 171
+value 13 goes to bot 67
+bot 195 gives low to bot 133 and high to bot 28
+bot 124 gives low to bot 67 and high to bot 196
+bot 109 gives low to output 7 and high to bot 74
+bot 25 gives low to bot 92 and high to bot 157
+bot 116 gives low to bot 15 and high to bot 3
+bot 140 gives low to bot 209 and high to bot 158
+bot 154 gives low to bot 95 and high to bot 79
+bot 92 gives low to bot 142 and high to bot 65
+bot 81 gives low to bot 85 and high to bot 41
+bot 33 gives low to bot 27 and high to bot 133
+bot 186 gives low to bot 70 and high to bot 185
+bot 73 gives low to bot 32 and high to bot 20
+bot 41 gives low to bot 112 and high to bot 56
+bot 89 gives low to bot 185 and high to bot 139
+bot 23 gives low to bot 177 and high to bot 12
+bot 125 gives low to bot 72 and high to bot 14
+bot 50 gives low to bot 154 and high to bot 149
+bot 21 gives low to bot 13 and high to bot 18
+bot 159 gives low to output 9 and high to bot 203
+bot 47 gives low to bot 136 and high to bot 63
+bot 143 gives low to bot 89 and high to bot 87
+bot 44 gives low to bot 73 and high to bot 118
+value 43 goes to bot 94
+bot 107 gives low to bot 97 and high to bot 156
+bot 70 gives low to bot 110 and high to bot 147
+bot 45 gives low to bot 129 and high to bot 83
+bot 43 gives low to bot 12 and high to bot 174
+value 41 goes to bot 164
+bot 74 gives low to output 18 and high to bot 130
+bot 136 gives low to bot 143 and high to bot 207
+bot 42 gives low to bot 163 and high to bot 177
+value 17 goes to bot 164
+bot 0 gives low to output 19 and high to bot 188
+bot 87 gives low to bot 139 and high to bot 127
+value 59 goes to bot 96
+bot 120 gives low to bot 168 and high to bot 91
+bot 198 gives low to bot 71 and high to bot 121
+bot 203 gives low to output 16 and high to output 1
+value 29 goes to bot 25
+bot 22 gives low to bot 55 and high to bot 103
+bot 11 gives low to bot 52 and high to bot 54
+bot 6 gives low to bot 11 and high to bot 131
+bot 31 gives low to output 13 and high to bot 0
+bot 126 gives low to bot 192 and high to bot 78
+bot 27 gives low to output 11 and high to bot 59
+bot 127 gives low to bot 57 and high to bot 1
+bot 60 gives low to bot 105 and high to bot 148
+bot 152 gives low to bot 189 and high to bot 165
+bot 100 gives low to bot 98 and high to bot 88
+bot 83 gives low to bot 155 and high to bot 44
+bot 123 gives low to bot 33 and high to bot 195
+bot 183 gives low to bot 83 and high to bot 90
+bot 71 gives low to bot 152 and high to bot 121
\ No newline at end of file
diff --git a/src/bin/day10.rs b/src/bin/day10.rs
new file mode 100644
index 0000000..d45661e
--- /dev/null
+++ b/src/bin/day10.rs
@@ -0,0 +1,168 @@
+use std::collections::HashMap;
+use std::io::{self, Read};
+use std::str::FromStr;
+
+#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash)]
+struct Chip(u32);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+struct Bot(u32);
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+struct Output(u32);
+
+#[derive(Clone, Copy, Default)]
+struct BotChips(Option<Chip>, Option<Chip>);
+
+impl BotChips {
+    fn add(&mut self, chip: Chip) {
+        match (self.0, self.1) {
+            (None, None) => {
+                self.0 = Some(chip);
+            },
+            (Some(low), None) if low < chip => {
+                self.1 = Some(chip);
+            },
+            (Some(high), None) => {
+                self.0 = Some(chip);
+                self.1 = Some(high);
+            },
+            _ => panic!("bot has too many chips"),
+        }
+    }
+
+    fn has_two(&self) -> bool {
+        self.0.is_some() && self.1.is_some()
+    }
+}
+
+#[derive(Clone, Copy)]
+enum Destination {
+    Bot(Bot),
+    Output(Output),
+}
+
+impl Destination {
+    fn from_pair(ty: &str, value: u32) -> Result<Self, ()> {
+        match ty {
+            "bot" => Ok(Destination::Bot(Bot(value))),
+            "output" => Ok(Destination::Output(Output(value))),
+            _ => Err(()),
+        }
+    }
+}
+
+#[derive(Default)]
+struct Instructions {
+    chips: HashMap<Chip, Bot>,
+    bots: HashMap<Bot, (Destination, Destination)>,
+}
+
+impl FromStr for Instructions {
+    type Err = ();
+    fn from_str(s: &str) -> Result<Self, ()> {
+        let mut instructions = Instructions::default();
+
+        for line in s.lines() {
+            let mut words = line.split(' ');
+            if words.next() == Some("value") {
+                let value = words.next().ok_or(())?.parse().map_err(|_| ())?;
+                let bot = words.nth(3).ok_or(())?.parse().map_err(|_| ())?;
+
+                instructions.chips.insert(Chip(value), Bot(bot));
+            } else {
+                let bot = words.next().ok_or(())?.parse().map_err(|_| ())?;
+                let low_type = words.nth(3).ok_or(())?;
+                let low_value = words.next().ok_or(())?.parse().map_err(|_| ())?;
+                let high_type = words.nth(3).ok_or(())?;
+                let high_value = words.next().ok_or(())?.parse().map_err(|_| ())?;
+
+                let low = Destination::from_pair(low_type, low_value)?;
+                let high = Destination::from_pair(high_type, high_value)?;
+
+                instructions.bots.insert(Bot(bot), (low, high));
+            }
+        }
+
+        Ok(instructions)
+    }
+}
+
+#[derive(Default)]
+struct State {
+    outputs: HashMap<Output, Vec<Chip>>,
+    bots: HashMap<Bot, BotChips>,
+    comparisons: HashMap<(Chip, Chip), Bot>,
+}
+
+impl State {
+    fn initialize(&mut self, instructions: &Instructions) {
+        for (&chip, &bot) in &instructions.chips {
+            self.bots.entry(bot).or_insert_with(Default::default).add(chip);
+        }
+    }
+
+    fn step(&mut self, instructions: &Instructions) -> bool {
+        let active_bots: Vec<Bot> = self.bots.iter()
+            .filter(|&(_, ref chips)| chips.has_two())
+            .map(|(&bot, _)| bot)
+            .collect();
+
+        if active_bots.is_empty() {
+            return false;
+        }
+
+        for bot in active_bots {
+            let (low, high) = {
+                let chips = self.bots.get_mut(&bot).unwrap();
+                (chips.0.take().unwrap(), chips.1.take().unwrap())
+            };
+            self.comparisons.insert((low, high), bot);
+
+            let &(low_dest, high_dest) = instructions.bots.get(&bot).unwrap();
+            self.add_to(low_dest, low);
+            self.add_to(high_dest, high);
+        }
+
+        true
+    }
+
+    fn add_to(&mut self, destination: Destination, chip: Chip) {
+        match destination {
+            Destination::Bot(bot) => {
+                self.bots.entry(bot).or_insert_with(Default::default).add(chip);
+            },
+            Destination::Output(output) => {
+                self.outputs.entry(output).or_insert_with(Vec::new).push(chip);
+            },
+        }
+    }
+}
+
+fn solve(comparison: (Chip, Chip), input: &str) -> Option<Bot> {
+    let instructions = input.parse().unwrap();
+    let mut state = State::default();
+    state.initialize(&instructions);
+    while state.step(&instructions) { }
+    state.comparisons.get(&comparison).cloned()
+}
+
+fn main() {
+    let mut input = String::new();
+    io::stdin().read_to_string(&mut input).unwrap();
+
+    println!("Part 1: {:?}", solve((Chip(17), Chip(61)), &input));
+}
+
+#[test]
+fn part1() {
+    let input = "
+value 5 goes to bot 2
+bot 2 gives low to bot 1 and high to bot 0
+value 3 goes to bot 1
+bot 1 gives low to output 1 and high to bot 0
+bot 0 gives low to output 2 and high to output 0
+value 2 goes to bot 2
+";
+    assert_eq!(Some(Bot(2)), solve((Chip(2), Chip(5)), input.trim()));
+}