feat: day 6

.aoc-cache/6.txt

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+Time:        58     99     64     69
+Distance:   478   2232   1019   1071

src/bin/day_6.rs

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+use aoc_2022::prelude::*;
+use color_eyre::eyre::ContextCompat;
+use std::fmt::Write;
+
+type Input = Vec<(isize, isize)>;
+
+fn parse(s: &str) -> Result<Input> {
+    let (time, distance) = s.split_once("\n")
+        .wrap_err("invalid format")?;
+    Ok(ints(time).into_iter().zip(ints(distance)).collect::<Vec<_>>())
+}
+
+fn race_calc((total_time, target_distance): (isize, isize)) -> usize {
+    let a = 1.0;
+    let b = -total_time as f64;
+    let c = target_distance as f64;
+    let v1 = (-b + (b*b - 4.0*a*c).sqrt()) / 2.0*a;
+    let v2 = (-b - (b*b - 4.0*a*c).sqrt()) / 2.0*a;
+    let min = v1.min(v2) + 0.00001;
+    let max = v1.max(v2) - 0.00001;
+    let min = min.ceil() as i64;
+    let max = max.floor() as i64;
+    (min..=max).count()
+}
+
+#[aoc(day = 6, parse = parse, test_cases = ["day_6.txt"])]
+fn day_6(mut input: Input) -> Result<()> {
+    // Part 1
+    println!("Part one: ");
+    let result: usize = input.iter().copied().map(race_calc).product();
+    println!("{result}");
+
+    // Part 2
+    println!("Part two: ");
+    let mut total_time = String::new();
+    let mut target_distance = String::new();
+    for (t, d) in &input {
+        write!(total_time, "{t}")?;
+        write!(target_distance, "{d}")?;
+    }
+    let total_time = total_time.parse()?;
+    let target_distance = target_distance.parse()?;
+    println!("{total_time} {target_distance}");
+    let result = race_calc((total_time, target_distance));
+    println!("{result}");
+
+    Ok(())
+}

test_cases/day_6.txt

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+Time:      7  15   30
+Distance:  9  40  200