129 lines
2.7 KiB
Rust
129 lines
2.7 KiB
Rust
#[derive(Debug)]
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enum Instruction {
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Addx(isize),
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Noop,
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}
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use Instruction::*;
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impl Instruction {
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pub fn from_line(line: &str) -> Self {
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let parts: Vec<&str> = line.split_ascii_whitespace().collect();
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if parts.len() == 2 && parts[0] == "addx" {
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let value = parts[1].parse::<isize>().unwrap();
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return Addx(value);
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}
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Noop
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}
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}
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// -----------------------------------------------------------------------------
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#[derive(Debug)]
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struct CPU {
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x: isize,
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}
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impl CPU {
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pub fn new() -> Self {
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CPU { x: 1 }
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}
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fn noop(&self) -> usize {
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1
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}
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fn addx(&mut self, i: isize) -> usize {
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self.x += i;
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2
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}
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pub fn get_x(&self) -> isize {
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self.x
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}
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pub fn run(&mut self, command: Instruction) -> usize {
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match command {
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Addx(i) => self.addx(i),
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Noop => self.noop(),
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}
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}
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}
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// -----------------------------------------------------------------------------
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#[derive(Debug)]
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struct CycleCounter {
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cpu: CPU,
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log: Vec<isize>,
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cycle: usize,
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}
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impl CycleCounter {
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pub fn new() -> Self {
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Self {
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cpu: CPU::new(),
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log: vec![1, 1],
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cycle: 1,
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}
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}
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fn run_line(&mut self, line: &str) {
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let x = self.cpu.get_x();
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let cycles = self.cpu.run(Instruction::from_line(line));
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for _ in 0..(cycles - 1) {
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self.cycle += 1;
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self.log.push(x);
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}
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self.cycle += 1;
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self.log.push(self.cpu.get_x());
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}
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pub fn get_signal_strength(&self, cycle: usize) -> usize {
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let x = self.log.get(cycle).unwrap();
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(*x as usize) * cycle
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}
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}
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// -----------------------------------------------------------------------------
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fn main() {
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let file_str = include_str!("input.txt");
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let mut cc = CycleCounter::new();
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file_str.lines().for_each(|line| cc.run_line(line));
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let sum: usize = [20usize, 60, 100, 140, 180, 220]
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.into_iter()
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.map(|n| cc.get_signal_strength(n))
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.sum();
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println!("Part 1: sum of signal strength: {}", sum);
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_get_signal_strength() {
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let file_str = include_str!("test-input.txt");
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let mut cc = CycleCounter::new();
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file_str.lines().for_each(|line| cc.run_line(line));
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assert_eq!(cc.get_signal_strength(20), 420);
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assert_eq!(cc.get_signal_strength(60), 1140);
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assert_eq!(cc.get_signal_strength(100), 1800);
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assert_eq!(cc.get_signal_strength(140), 2940);
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assert_eq!(cc.get_signal_strength(180), 2880);
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assert_eq!(cc.get_signal_strength(220), 3960);
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}
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}
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