feat: day 7

allow to only run specific days

Cargo.toml

@@ -3,6 +3,17 @@ name = "aoc2024"
 version = "0.1.0"
 edition = "2021"
 
+[features]
+full = ["day1", "day2", "day3", "day4", "day5", "day6", "day7"]
+default = ["full"]
+day1 = []
+day2 = []
+day3 = []
+day4 = []
+day5 = []
+day6 = []
+day7 = []
+
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

inputs/day07/example.txt

@@ -0,0 +1,9 @@
+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20

src/day07.rs

@@ -0,0 +1,92 @@
+pub fn pt1(input: &str) -> usize {
+    input
+        .lines()
+        .map(|line| line.split_once(": ").unwrap())
+        .map(|(res, args)| {
+            (
+                res.parse::<usize>().unwrap(),
+                args.split(' ')
+                    .flat_map(str::parse::<usize>)
+                    .collect::<Vec<_>>(),
+            )
+        })
+        .filter(can_calibrate)
+        .map(|(val, _)| val)
+        .sum()
+}
+fn can_calibrate((res, args): &(usize, Vec<usize>)) -> bool {
+    (0..(2usize << args.len())).any(|mut i| {
+        let mut arg_clone = args.iter();
+        let mut current_res = *arg_clone.next().unwrap();
+        for arg in arg_clone {
+            let op = i & 1;
+            if op == 1 {
+                current_res += arg;
+            } else {
+                current_res *= arg;
+            }
+            i >>= 1;
+        }
+        current_res == *res
+    })
+}
+
+fn can_calibrate_concat((res, args): &(usize, Vec<usize>)) -> bool {
+    (0..(3usize.pow(u32::try_from(args.len()).unwrap()))).any(|mut i| {
+        let mut arg_clone = args.iter();
+        let mut current_res = *arg_clone.next().unwrap();
+        for arg in arg_clone {
+            let op = i % 3;
+            match op {
+                0 => current_res += arg,
+                1 => current_res *= arg,
+                2 => {
+                    current_res *= 10usize.pow(u32::try_from(arg.to_string().len()).unwrap());
+                    current_res += arg;
+                }
+                _ => unreachable!(),
+            }
+            i /= 3;
+            if current_res > *res {
+                return false;
+            }
+        }
+        current_res == *res
+    })
+}
+pub fn pt2(input: &str) -> usize {
+    input
+        .lines()
+        .map(|line| line.split_once(": ").unwrap())
+        .map(|(res, args)| {
+            (
+                res.parse::<usize>().unwrap(),
+                args.split(' ')
+                    .flat_map(str::parse::<usize>)
+                    .collect::<Vec<_>>(),
+            )
+        })
+        .filter(can_calibrate_concat)
+        .map(|(val, _)| val)
+        .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{pt1, pt2};
+    use std::fs::read_to_string;
+
+    #[test]
+    pub fn test_pt1() {
+        let input =
+            read_to_string("./inputs/day07/example.txt").expect("Missing example.txt for day07");
+        assert_eq!(pt1(&input), 3749)
+    }
+    #[test]
+    pub fn test_pt2() {
+        let input =
+            read_to_string("./inputs/day07/example.txt").expect("Missing example.txt for day07");
+
+        assert_eq!(pt2(&input), 11387)
+    }
+}

src/main.rs

@@ -1,21 +1,37 @@
 use std::{fmt::Display, fs::read_to_string, time::Instant};
 
+#[cfg(feature = "day1")]
 mod day01;
+#[cfg(feature = "day2")]
 mod day02;
+#[cfg(feature = "day3")]
 mod day03;
+#[cfg(feature = "day4")]
 mod day04;
+#[cfg(feature = "day5")]
 mod day05;
+#[cfg(feature = "day6")]
 mod day06;
+#[cfg(feature = "day7")]
+mod day07;
 
 fn main() {
     color_eyre::install().unwrap();
     tracing_subscriber::fmt().init();
+    #[cfg(feature = "day1")]
     solve_day(1, day01::pt1, day01::pt2);
+    #[cfg(feature = "day2")]
     solve_day(2, day02::pt1, day02::pt2);
+    #[cfg(feature = "day3")]
     solve_day(3, day03::pt1, day03::pt2);
+    #[cfg(feature = "day4")]
     solve_day(4, day04::pt1, day04::pt2);
+    #[cfg(feature = "day5")]
     solve_day(5, day05::pt1, day05::pt2);
+    #[cfg(feature = "day6")]
     solve_day(6, day06::pt1, day06::pt2);
+    #[cfg(feature = "day7")]
+    solve_day(7, day07::pt1, day07::pt2);
 }
 
 fn solve_day<Fa, Fb, Ta, Tb>(day: u8, part_a: Fa, part_b: Fb)
@@ -25,12 +41,17 @@ where
     Fb: Fn(&str) -> Tb,
     Tb: Display,
 {
-    let input = read_to_string(format!("./inputs/day{day:02}/input.txt"))
-        .unwrap_or_else(|_| panic!("Missing input.txt for day{day:02}"));
-    let start = Instant::now();
-    let result_a = part_a(&input);
-    tracing::info!("[{day:02}] Part A: {result_a} \tin {:?}", start.elapsed());
-    let start = Instant::now();
-    let result_b = part_b(&input);
-    tracing::info!("[{day:02}] Part B: {result_b} \tin {:?}", start.elapsed());
+    match read_to_string(format!("./inputs/day{day:02}/input.txt")) {
+        Ok(input) => {
+            let start = Instant::now();
+            let result_a = part_a(&input);
+            tracing::info!("[{day:02}] Part A: {result_a} \tin {:?}", start.elapsed());
+            let start = Instant::now();
+            let result_b = part_b(&input);
+            tracing::info!("[{day:02}] Part B: {result_b} \tin {:?}", start.elapsed());
+        }
+        Err(_) => {
+            tracing::warn!("could not open ./inputs/day{day:02}/input.txt");
+        },
+    }
 }