81 lines
1.8 KiB
Rust
81 lines
1.8 KiB
Rust
use std::error::Error;
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use std::fs;
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#[derive(Debug, Copy, Clone)]
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enum Shape {
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Rock,
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Paper,
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Scissors,
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}
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use Shape::*;
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impl From<char> for Shape {
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fn from(c: char) -> Self {
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match c {
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'A' | 'X' => Rock,
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'B' | 'Y' => Paper,
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'C' | 'Z' => Scissors,
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_ => panic!("Invalid char: {}", c),
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}
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}
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}
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impl Shape {
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fn get_score(&self) -> u32 {
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match self {
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Rock => 1,
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Paper => 2,
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Scissors => 3,
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}
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}
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}
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fn get_outcome_score(them: Shape, you: Shape) -> u32 {
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match (them, you) {
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// Loss
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(Rock, Scissors) | (Paper, Rock) | (Scissors, Paper) => 0,
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// Tie
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(Rock, Rock) | (Paper, Paper) | (Scissors, Scissors) => 3,
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// Win
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(Rock, Paper) | (Paper, Scissors) | (Scissors, Rock) => 6,
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}
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}
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fn get_round_score(them: char, you: char) -> u32 {
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let them = Shape::from(them);
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let you = Shape::from(you);
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let shape_score = you.get_score();
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let outcome_score = get_outcome_score(them, you);
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shape_score + outcome_score
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}
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fn get_scores(lines: Vec<&str>) -> Vec<u32> {
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lines
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.into_iter()
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.map(|line| {
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// This is trying to be too clever
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let [them, _, you]: [char; 3] = line.chars().collect::<Vec<char>>().try_into().unwrap();
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get_round_score(them, you)
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})
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.collect()
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}
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fn main() -> Result<(), Box<dyn Error>> {
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let file_str = fs::read_to_string("input.txt")?;
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let lines: Vec<&str> = file_str.lines().collect();
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let scores = get_scores(lines);
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let total = scores
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.into_iter()
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.reduce(|accum, item| accum + item)
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.unwrap();
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println!("Part 1: Final score: {}", total);
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Ok(())
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}
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