day 8 part 1 solution

Signed-off-by: Stephen Waits <swaits@amazon.com>

data/input-08.txt

@@ -0,0 +1,654 @@
+acc +50
+acc -11
+nop +378
+acc +15
+jmp +508
+acc -3
+jmp +1
+jmp +135
+jmp +1
+acc -6
+acc +14
+acc +32
+jmp +315
+acc -16
+jmp +249
+jmp +283
+acc -14
+acc +5
+acc +29
+jmp +366
+acc +22
+jmp +77
+acc +19
+jmp +496
+acc -2
+acc -16
+nop +284
+nop +36
+jmp +178
+jmp +281
+acc +32
+acc +45
+acc +16
+jmp +403
+nop +86
+nop +32
+acc +10
+jmp +47
+acc -13
+acc +35
+jmp +270
+jmp +1
+acc +34
+acc -3
+nop +116
+jmp +552
+acc +27
+nop +113
+jmp +495
+acc -18
+acc +47
+acc +19
+jmp +180
+acc -8
+acc -1
+acc -14
+acc +17
+jmp +431
+acc +49
+acc +22
+acc +39
+acc +28
+jmp +74
+jmp -10
+acc -5
+acc +35
+jmp +251
+acc +31
+acc -11
+jmp -49
+acc -12
+acc +49
+jmp +36
+acc -19
+acc -9
+acc +11
+acc -1
+jmp +419
+jmp +307
+acc +36
+jmp +563
+acc +32
+acc +1
+jmp +270
+acc +17
+jmp +464
+jmp +133
+acc +29
+acc +31
+jmp +394
+acc -2
+jmp +94
+acc +44
+acc +28
+acc +32
+jmp +543
+acc +18
+jmp +325
+acc +16
+acc +42
+jmp +315
+acc -6
+jmp +371
+acc +41
+acc +29
+jmp +44
+acc -19
+jmp +393
+acc +4
+jmp +81
+acc +25
+jmp +108
+acc -18
+jmp +1
+jmp +1
+acc +34
+jmp +124
+acc +25
+acc +45
+jmp -46
+acc -11
+acc +43
+acc +50
+jmp +6
+acc +3
+acc -6
+acc +38
+acc +9
+jmp +402
+acc +26
+nop +97
+acc +26
+jmp +115
+acc -1
+acc +2
+jmp +7
+acc +38
+nop +5
+jmp -75
+acc +41
+nop +470
+jmp +15
+acc -15
+acc +19
+acc +22
+jmp +240
+acc +14
+acc +26
+jmp +71
+acc +38
+acc +25
+jmp +349
+acc +25
+acc +31
+acc +41
+jmp +419
+jmp -69
+acc +50
+nop +218
+jmp -106
+nop +225
+jmp +307
+acc +33
+acc -4
+acc +36
+jmp -57
+acc +14
+acc +0
+acc -2
+jmp +184
+acc +47
+nop +161
+acc -4
+jmp -149
+jmp +103
+acc +39
+acc +25
+acc +8
+acc +2
+jmp +364
+acc +48
+jmp +241
+nop +432
+acc +9
+jmp +304
+acc +20
+jmp +223
+acc +12
+acc +21
+jmp +121
+acc +12
+acc +47
+acc +50
+acc +8
+jmp +283
+jmp +1
+jmp +81
+acc +22
+acc -6
+jmp +1
+acc -9
+jmp +340
+acc -9
+acc +5
+acc +11
+jmp +204
+acc -13
+acc +12
+jmp +322
+acc +38
+acc +50
+nop +211
+jmp +91
+acc +31
+acc +34
+jmp -95
+acc +12
+acc +13
+jmp -172
+nop +419
+jmp +1
+nop -191
+acc +48
+jmp +157
+acc +22
+acc +27
+jmp +61
+acc +23
+nop +181
+jmp -121
+nop +367
+jmp -168
+jmp +1
+nop -218
+jmp -142
+jmp +295
+jmp +112
+acc +9
+acc -12
+jmp +114
+acc +50
+jmp -28
+acc +18
+nop -223
+acc +37
+acc -14
+jmp +169
+acc +0
+acc +42
+jmp +115
+acc +2
+acc +31
+jmp -189
+acc +7
+acc +45
+acc -2
+acc +34
+jmp -121
+acc -13
+acc +4
+nop -94
+acc +34
+jmp +123
+acc -11
+acc -13
+jmp -29
+acc -11
+nop -169
+acc -11
+nop +369
+jmp +189
+acc -4
+jmp +20
+nop +19
+acc -13
+nop +368
+jmp -79
+acc -19
+acc +23
+acc -7
+acc -11
+jmp +36
+acc -18
+acc +31
+nop +349
+acc +11
+jmp -106
+acc +43
+jmp +185
+acc +20
+nop +297
+jmp +138
+acc +8
+acc +26
+acc -2
+jmp -18
+nop -276
+jmp +44
+jmp +1
+acc +39
+jmp +314
+acc +0
+jmp -194
+acc +32
+acc +17
+acc +43
+jmp -298
+acc +28
+acc -10
+jmp -103
+acc -17
+acc +3
+jmp +25
+acc +35
+acc +7
+acc -2
+jmp -39
+acc +19
+acc +19
+acc -8
+jmp -282
+jmp -275
+acc -7
+jmp +196
+acc +14
+acc +5
+jmp +6
+acc -7
+jmp +29
+nop +275
+acc -12
+jmp +165
+acc +21
+acc +4
+jmp +95
+acc +15
+jmp -283
+jmp +199
+acc -9
+acc +0
+jmp -220
+acc +28
+acc +1
+jmp -313
+acc +13
+acc -5
+acc +38
+jmp +62
+acc +43
+jmp -159
+acc -14
+acc +44
+jmp -314
+acc +3
+acc +34
+jmp +47
+jmp -171
+acc +27
+acc +11
+acc +16
+jmp +16
+acc +27
+acc +40
+jmp +66
+acc +30
+acc -15
+jmp +177
+acc +36
+acc +41
+jmp -189
+acc -19
+jmp +106
+nop +271
+nop -176
+acc +13
+jmp +40
+nop +33
+jmp -324
+acc +18
+jmp -76
+acc +38
+acc +39
+acc +34
+jmp +231
+jmp -131
+acc +46
+acc +38
+acc -3
+jmp -161
+acc +31
+acc +10
+jmp +158
+acc -18
+acc +46
+jmp -291
+jmp +48
+acc +18
+acc +36
+acc +16
+jmp -77
+acc +9
+jmp -289
+acc +38
+jmp -388
+nop +137
+acc +42
+acc +17
+nop -37
+jmp -145
+jmp -336
+acc +46
+acc -18
+acc -13
+acc +21
+jmp -97
+acc +49
+nop -189
+acc +21
+jmp -186
+acc +25
+acc +37
+jmp +193
+jmp +1
+acc -14
+acc +4
+jmp +87
+acc +3
+nop -95
+jmp -243
+acc +30
+acc +35
+jmp -128
+jmp +1
+nop +55
+acc +48
+jmp +129
+jmp +1
+acc +37
+jmp -326
+acc -2
+acc -13
+acc +37
+jmp -72
+acc +23
+jmp +130
+acc +18
+acc +0
+acc +36
+jmp -345
+acc +0
+acc +23
+acc +10
+jmp +1
+jmp -112
+nop -430
+acc +8
+acc +42
+jmp +1
+jmp +180
+nop -16
+acc +22
+jmp +1
+acc +2
+jmp +43
+acc +29
+acc +23
+acc -2
+jmp -364
+acc +14
+jmp -250
+acc -11
+nop -359
+jmp +132
+jmp -24
+nop +90
+acc +32
+jmp -461
+jmp -311
+acc +11
+acc +21
+jmp -320
+jmp -194
+jmp -165
+acc +43
+acc +5
+acc +12
+jmp -419
+jmp -467
+acc +47
+acc +35
+jmp +133
+acc +10
+nop -394
+acc +35
+nop -109
+jmp -298
+acc -10
+nop -451
+jmp -445
+jmp +57
+acc +31
+nop -1
+jmp -59
+acc +19
+acc +7
+jmp -5
+acc +31
+acc +0
+acc +29
+acc -8
+jmp -118
+jmp -119
+acc +35
+jmp -339
+acc +14
+nop +28
+acc +0
+acc +25
+jmp -265
+acc -9
+acc +29
+jmp -365
+nop +19
+acc +31
+acc +16
+jmp -116
+jmp -442
+acc +24
+acc -3
+jmp -505
+acc -5
+jmp -485
+acc -12
+acc +15
+jmp +1
+jmp -16
+acc +23
+nop -135
+jmp +26
+acc -16
+jmp -374
+jmp -171
+jmp -518
+acc +23
+acc +23
+jmp -282
+nop -78
+nop -230
+jmp -285
+acc +39
+acc +31
+jmp -219
+acc -18
+jmp +1
+acc +43
+jmp -175
+acc +46
+nop -391
+jmp -305
+acc -11
+acc +41
+acc +33
+acc -9
+jmp +70
+nop -8
+acc -3
+acc -16
+acc +8
+jmp -139
+nop -237
+acc +1
+nop -405
+acc +16
+jmp +14
+acc +0
+acc +35
+acc +26
+acc +43
+jmp +71
+nop -187
+nop -188
+jmp -7
+acc +34
+acc +11
+nop -35
+jmp -104
+jmp -37
+jmp +1
+acc +37
+acc +1
+nop -78
+jmp +19
+acc +35
+acc +35
+acc -3
+acc +0
+jmp -377
+acc +49
+jmp -519
+acc -18
+acc -5
+acc -15
+nop -76
+jmp -530
+acc +7
+acc +0
+jmp -19
+acc +15
+acc +37
+jmp -79
+jmp -339
+nop -398
+acc -16
+jmp +20
+acc -15
+acc -5
+acc +20
+acc -12
+jmp -21
+acc +39
+acc +32
+acc +34
+jmp -330
+acc +48
+acc +2
+acc -8
+acc -15
+jmp -231
+acc +35
+acc -16
+acc +26
+nop -547
+jmp -548
+acc +6
+acc +20
+acc +1
+jmp -439
+jmp -310
+acc +7
+acc +18
+jmp -58
+nop -444
+jmp -423
+acc -5
+jmp -40
+acc -14
+acc -11
+nop -283
+jmp -122
+acc +13
+acc +5
+nop -259
+acc +12
+jmp +1

data/output-08.txt

@@ -0,0 +1,2 @@
+2025
+0

src/day08.rs

@@ -0,0 +1,133 @@
+// ==== day 8
+
+use crate::utils;
+use anyhow::{anyhow, Result};
+use std::str::FromStr;
+
+#[derive(Debug)]
+enum Instruction {
+    Acc(i32),
+    Jmp(i32),
+    Nop(i32),
+}
+
+impl FromStr for Instruction {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let parsed: Vec<&str> = s.trim().split(' ').collect();
+        if parsed.len() != 2 {
+            return Err(anyhow!("instruction parse error"));
+        }
+        let opcode = parsed[0];
+        let operand = parsed[1].parse::<i32>()?;
+
+        match opcode {
+            "acc" => Ok(Instruction::Acc(operand)),
+            "jmp" => Ok(Instruction::Jmp(operand)),
+            "nop" => Ok(Instruction::Nop(operand)),
+            _ => Err(anyhow!("unknown instruction")),
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+struct Console {
+    pc: usize,                 // program counter
+    hits: Vec<usize>,          // instruction hits
+    accumulator: i32,          // accumulator (starts at 0)
+    program: Vec<Instruction>, // program is just an array of instructions
+}
+
+impl FromStr for Console {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let memory: Vec<Instruction> = s
+            .lines()
+            .map(|l| Instruction::from_str(l).unwrap())
+            .collect();
+        Ok(Console {
+            pc: 0,
+            hits: vec![0; memory.len()],
+            accumulator: 0,
+            program: memory,
+        })
+    }
+}
+
+#[derive(PartialEq)]
+enum Status {
+    Running,
+    Completed,
+    Halted,
+}
+
+impl Console {
+    fn reset(&mut self) {
+        self.pc = 0;
+        self.accumulator = 0;
+        self.hits = vec![0; self.program.len()];
+    }
+
+    fn get_run_state(&self) -> Status {
+        // check pc
+        if !(0..self.program.len()).contains(&self.pc) {
+            Status::Completed
+        }
+        // guard against infinite loops
+        else if self.hits[self.pc] > 0 {
+            Status::Halted
+        } else {
+            Status::Running
+        }
+    }
+
+    fn step(&mut self) -> Status {
+        // verify we're running
+        if self.get_run_state() != Status::Running {
+            return self.get_run_state();
+        }
+
+        // execute instruction at pc
+        self.hits[self.pc] += 1;
+        match self.program[self.pc] {
+            Instruction::Acc(n) => {
+                self.accumulator += n;
+                self.pc += 1;
+            }
+            Instruction::Jmp(n) => {
+                if n < 0 {
+                    self.pc -= n.abs() as usize;
+                } else {
+                    self.pc += n as usize;
+                }
+            }
+            Instruction::Nop(_) => {
+                self.pc += 1;
+            }
+        }
+        Status::Running
+    }
+
+    fn run(&mut self) -> i32 {
+        self.reset();
+        while self.step() == Status::Running {}
+        self.accumulator
+    }
+}
+
+pub fn run() -> Result<(i32, i32)> {
+    let data = utils::read_file("data/input-08.txt")?;
+    let answers = utils::read_i64s("data/output-08.txt")?;
+
+    let mut console = Console::from_str(&data)?;
+    println!("{:?}", console);
+
+    let p1 = console.run();
+    let p2 = 0;
+
+    assert_eq!(p1, answers[0] as i32);
+    assert_eq!(p2, answers[1] as i32);
+    Ok((p1, p2))
+}

src/main.rs

@@ -7,6 +7,7 @@ mod day04;
 mod day05;
 mod day06;
 mod day07;
+mod day08;
 mod utils;
 
 // TODO
@@ -27,5 +28,6 @@ fn main() -> Result<()> {
     println!("Day 05: {:?}", day05::run()?);
     println!("Day 06: {:?}", day06::run()?);
     println!("Day 07: {:?}", day07::run()?);
+    println!("Day 08: {:?}", day08::run()?);
     Ok(())
 }