2020: day08: part 1

aoc2020/benches/bench.rs

@@ -7,6 +7,7 @@ use aoc2020::day04;
 use aoc2020::day05;
 use aoc2020::day06;
 use aoc2020::day07;
+use aoc2020::day08;
 
 fn aoc2020_all(c: &mut Criterion) {
     c.bench_function("day01", |b| b.iter(|| day01::run().unwrap()));
@@ -16,6 +17,7 @@ fn aoc2020_all(c: &mut Criterion) {
     c.bench_function("day05", |b| b.iter(|| day05::run().unwrap()));
     c.bench_function("day06", |b| b.iter(|| day06::run().unwrap()));
     c.bench_function("day07", |b| b.iter(|| day07::run().unwrap()));
+    c.bench_function("day08", |b| b.iter(|| day08::run().unwrap()));
 }
 
 criterion_group! {

aoc2020/input/day08.txt

@@ -0,0 +1,605 @@
+acc +14
+acc +11
+nop +422
+acc +14
+jmp +443
+acc +21
+nop +524
+acc -2
+jmp +279
+jmp +1
+acc +28
+acc +11
+jmp +576
+acc +32
+acc -12
+acc -8
+jmp +291
+nop +542
+acc +41
+jmp +320
+acc +40
+jmp +96
+jmp +85
+acc +38
+acc +8
+jmp +333
+acc +44
+nop +231
+acc +40
+jmp +323
+acc +18
+jmp +251
+acc -1
+jmp +385
+acc -9
+acc +48
+acc +20
+acc +34
+jmp +150
+nop +203
+acc +4
+acc +32
+acc +44
+jmp +168
+acc +26
+acc +46
+acc +40
+jmp -30
+jmp +182
+acc +18
+jmp +404
+nop +142
+jmp +84
+acc +30
+acc +10
+jmp +1
+acc +40
+jmp +370
+jmp +381
+jmp +239
+acc -2
+acc +47
+acc -4
+jmp +295
+jmp -38
+acc +40
+acc +44
+acc +4
+acc +4
+jmp +156
+acc +31
+acc +20
+acc +0
+acc -12
+jmp -48
+acc +32
+acc +38
+jmp +1
+acc -6
+jmp +375
+acc +33
+acc +27
+acc +28
+jmp +107
+acc +1
+acc +6
+nop +136
+jmp +85
+acc +31
+acc +49
+acc +46
+jmp +167
+acc +5
+acc -5
+jmp +148
+acc +22
+acc +44
+acc -8
+acc -2
+jmp -60
+nop +354
+jmp +59
+acc +48
+nop +473
+acc -7
+acc +4
+jmp +105
+jmp +456
+acc +16
+acc +33
+acc +24
+jmp -4
+acc +36
+acc +10
+nop +441
+jmp +268
+jmp +388
+acc +0
+acc +27
+acc -1
+jmp -60
+nop +90
+jmp -90
+acc +48
+acc +30
+jmp +284
+acc +4
+acc +6
+acc +1
+acc -10
+jmp +95
+acc +35
+jmp +235
+acc +31
+acc -19
+jmp -96
+jmp +326
+acc -7
+acc +0
+acc -1
+jmp +53
+acc +15
+acc -14
+jmp +450
+nop +8
+acc -2
+acc -1
+acc +17
+jmp -25
+nop +444
+jmp +65
+jmp -86
+acc +44
+acc +16
+acc +32
+acc -11
+jmp +32
+acc +14
+acc +28
+jmp +123
+jmp +127
+jmp -44
+acc +42
+acc +24
+acc -3
+acc +4
+jmp +219
+acc +28
+acc +30
+acc -14
+acc -11
+jmp +67
+acc +5
+acc +43
+acc +23
+nop +73
+jmp +176
+acc +28
+acc +8
+acc +42
+acc +44
+jmp +278
+acc +9
+acc +46
+acc +0
+acc +30
+jmp +72
+jmp +317
+jmp +352
+jmp +273
+jmp +137
+nop +364
+jmp +249
+nop +79
+jmp +1
+jmp -147
+acc -10
+acc -1
+acc +12
+acc +27
+jmp +147
+acc -5
+acc +7
+jmp +63
+acc +33
+acc +32
+nop +81
+jmp -185
+acc +44
+jmp +215
+jmp +187
+acc +14
+acc +38
+jmp -113
+jmp +267
+acc -9
+acc +21
+acc -5
+jmp +143
+nop -57
+nop +281
+jmp -170
+jmp +267
+nop -131
+jmp -83
+acc -6
+jmp -95
+acc -9
+acc -8
+jmp +184
+acc +32
+acc -16
+jmp +171
+acc +5
+acc +22
+acc -7
+acc +20
+jmp +45
+acc +48
+jmp +239
+acc -4
+jmp +75
+acc -18
+jmp -178
+nop +349
+acc -12
+nop +313
+jmp -57
+acc +7
+acc +6
+jmp -241
+acc +19
+jmp +320
+acc +13
+jmp -61
+acc +0
+nop +337
+jmp +66
+acc +27
+acc -11
+acc -7
+jmp +315
+acc +23
+acc +26
+acc -5
+jmp +132
+acc +45
+acc +21
+acc -12
+jmp +158
+acc +19
+jmp +176
+acc +43
+jmp +124
+nop +227
+nop -236
+acc +11
+jmp +1
+jmp -67
+acc +21
+jmp +161
+jmp +86
+acc +26
+acc +7
+jmp +246
+acc +0
+jmp +215
+jmp +1
+acc +16
+jmp -257
+acc +2
+jmp +281
+nop -10
+acc +46
+jmp +124
+acc +13
+acc +24
+jmp +204
+jmp +1
+acc +23
+jmp +225
+nop -243
+jmp +167
+jmp +1
+jmp -142
+acc -15
+jmp -113
+acc +27
+acc -18
+acc +12
+jmp -259
+nop +74
+acc +35
+acc +42
+acc -4
+jmp -166
+nop +87
+nop +86
+acc +18
+acc -2
+jmp +212
+acc -8
+jmp -313
+acc +36
+acc -11
+jmp -233
+jmp +237
+nop +67
+acc +16
+nop -57
+jmp -92
+acc +48
+acc +2
+acc +21
+jmp +33
+acc -15
+jmp +145
+acc +26
+jmp -254
+acc +30
+acc +4
+acc -1
+acc -14
+jmp -64
+acc +32
+acc +8
+jmp -131
+acc -13
+jmp +138
+acc +5
+acc +4
+jmp -4
+acc +37
+nop -278
+acc +28
+acc +17
+jmp -215
+jmp -104
+nop -241
+jmp -43
+jmp -2
+acc +5
+acc -1
+jmp +151
+jmp +1
+acc +21
+jmp +19
+acc +40
+jmp +91
+acc +50
+nop +202
+acc -12
+jmp -333
+nop -66
+acc +42
+acc +7
+jmp +1
+jmp +47
+acc +32
+acc +29
+acc +42
+nop -8
+jmp +52
+jmp -299
+jmp +40
+acc +36
+acc -5
+acc +39
+jmp -116
+acc +19
+acc +30
+acc +39
+acc -1
+jmp -276
+jmp -245
+acc +6
+jmp -185
+acc +50
+acc +14
+acc -7
+jmp -325
+acc +33
+jmp -279
+nop +173
+acc +15
+acc -17
+jmp -33
+acc +20
+jmp -101
+acc -17
+jmp -335
+nop -8
+jmp +22
+acc +0
+acc +4
+jmp -133
+nop -81
+jmp +64
+jmp -306
+acc -19
+acc +31
+acc +47
+acc +26
+jmp +55
+jmp -402
+acc +13
+jmp -375
+acc +6
+acc -1
+acc -6
+acc +49
+jmp -28
+acc -7
+jmp -203
+jmp -395
+acc +5
+acc +38
+acc +10
+jmp +130
+jmp +161
+jmp -382
+acc +45
+jmp +113
+acc +38
+acc +48
+acc +46
+jmp +126
+acc -1
+acc -10
+acc +4
+acc +2
+jmp -425
+acc +0
+jmp -80
+acc +4
+jmp -202
+acc +25
+acc +8
+jmp -398
+jmp -307
+acc +3
+jmp +17
+acc +13
+acc +33
+acc +7
+jmp -381
+acc +5
+acc +12
+jmp -308
+jmp +1
+acc +3
+acc -14
+acc +46
+jmp -415
+acc +31
+acc +7
+acc +28
+jmp -419
+jmp -175
+jmp +1
+jmp -141
+acc +20
+nop -35
+jmp -36
+acc -6
+jmp +108
+nop +1
+jmp +8
+jmp -49
+jmp -389
+acc +24
+nop -482
+acc +41
+acc +25
+jmp -167
+nop -26
+jmp -198
+nop -199
+acc +23
+acc -19
+jmp -202
+jmp +58
+acc +3
+jmp -237
+acc +44
+acc +42
+acc +22
+acc +5
+jmp -307
+acc +45
+nop -418
+acc +41
+nop -88
+jmp +63
+acc +12
+nop -56
+acc -19
+jmp +55
+acc -13
+acc -7
+jmp -213
+acc +42
+jmp -88
+acc +20
+jmp -115
+acc +6
+jmp -57
+acc +25
+acc +49
+jmp -43
+jmp -322
+jmp -456
+acc +7
+acc +40
+acc +35
+jmp -518
+nop -461
+acc +43
+acc +33
+jmp +7
+acc +27
+jmp +5
+acc -15
+acc -19
+acc -2
+jmp -238
+acc +49
+acc +48
+acc -16
+jmp +34
+acc -6
+acc +49
+acc -4
+acc +4
+jmp +1
+acc +35
+nop -264
+jmp -234
+jmp -365
+jmp -436
+acc +20
+acc +36
+jmp -426
+acc +39
+acc +20
+jmp -343
+nop -443
+jmp -325
+jmp -127
+nop -560
+acc +10
+jmp -511
+jmp -455
+acc -16
+acc +18
+jmp -61
+acc +26
+jmp -285
+jmp +1
+nop -397
+acc +12
+nop -67
+jmp -371
+acc +27
+acc +13
+jmp -395
+acc +44
+jmp -565
+acc +1
+jmp -21
+nop -428
+acc -4
+jmp -265
+acc +48
+acc +10
+acc +46
+jmp -202
+acc -4
+acc -10
+jmp -152
+acc +17
+acc -10
+acc +22
+acc +10
+jmp +1

aoc2020/input/day08_provided.txt

@@ -0,0 +1,9 @@
+nop +0
+acc +1
+jmp +4
+acc +3
+jmp -3
+acc -99
+acc +1
+jmp -4
+acc +6

aoc2020/src/day08.rs

@@ -0,0 +1,105 @@
+use std::collections::HashSet;
+use std::fmt::Write;
+
+use aoc::err;
+
+const INPUT: &str = include_str!("../input/day08.txt");
+
+pub fn run() -> aoc::Result<String> {
+    let mut res = String::with_capacity(128);
+
+    writeln!(res, "part 1: {}", part1(INPUT)?)?;
+
+    Ok(res)
+}
+
+fn part1(input: &str) -> aoc::Result<i64> {
+    let instructions = input
+        .lines()
+        .map(|line| line.parse())
+        .collect::<aoc::Result<Vec<Instruction>>>()?;
+
+    let mut interpreter = Interpreter::new(instructions);
+
+    let mut set = HashSet::new();
+
+    loop {
+        if !set.insert(interpreter.idx) {
+            break;
+        }
+
+        interpreter.step();
+    }
+
+    Ok(interpreter.accumulator)
+}
+
+struct Interpreter {
+    idx: usize,
+    accumulator: i64,
+    memory: Vec<Instruction>,
+}
+
+impl Interpreter {
+    fn new(instructions: Vec<Instruction>) -> Self {
+        Self {
+            idx: 0,
+            accumulator: 0,
+            memory: instructions,
+        }
+    }
+
+    fn step(&mut self) {
+        match self.memory[self.idx] {
+            Instruction::Acc(arg) => {
+                self.accumulator += arg;
+                self.idx += 1;
+            }
+            Instruction::Jmp(offset) => self.idx = self.idx.wrapping_add(offset as usize),
+            Instruction::Nop => self.idx += 1,
+        }
+    }
+}
+
+enum Instruction {
+    Acc(i64),
+    Jmp(i64),
+    Nop,
+}
+
+impl std::str::FromStr for Instruction {
+    type Err = aoc::Error;
+
+    fn from_str(s: &str) -> aoc::Result<Self> {
+        let space = s.find(' ').ok_or_else(|| err!("couldn't split on space"))?;
+
+        let inst = &s[..space];
+        let arg = s[(space + 1)..]
+            .parse()
+            .map_err(|e| err!("couldn't parse argument for instruction: {}", e))?;
+
+        Ok(match inst {
+            "acc" => Self::Acc(arg),
+            "jmp" => Self::Jmp(arg),
+            "nop" => Self::Nop,
+            _ => return Err(err!("unrecognized instruction `{}`", inst)),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const PROVIDED: &str = include_str!("../input/day08_provided.txt");
+
+    #[test]
+    fn part1_provided() {
+        assert_eq!(part1(PROVIDED).unwrap(), 5);
+    }
+
+    #[test]
+    fn part1_real() {
+        assert_eq!(part1(INPUT).unwrap(), 1675);
+    }
+}

aoc2020/src/lib.rs

@@ -5,3 +5,4 @@ pub mod day04;
 pub mod day05;
 pub mod day06;
 pub mod day07;
+pub mod day08;

aoc2020/src/main.rs

@@ -8,6 +8,7 @@ use aoc2020::day04;
 use aoc2020::day05;
 use aoc2020::day06;
 use aoc2020::day07;
+use aoc2020::day08;
 
 fn main() -> Result<()> {
     let days: &[DayFunc] = &[
@@ -18,6 +19,7 @@ fn main() -> Result<()> {
         day05::run,
         day06::run,
         day07::run,
+        day08::run,
     ];
 
     aoc::run(days)