day3 solution 1

1 files changed, 36 insertions, 0 deletions

diff --git a/src/bin/day3.rs b/src/bin/day3.rs
new file mode 100644
index 0000000..02cb385
--- /dev/null
+++ b/src/bin/day3.rs
@@ -0,0 +1,36 @@
+use regex::Regex;
+
+static DAY: u8 = 3;
+
+fn main() {
+    let input = advent::read_lines(DAY);
+    println!("{DAY}a: {}", sum_multiplications(&input));
+    println!("{DAY}b: {}", 0);
+}
+
+fn sum_multiplications(input: &[String]) -> u32 {
+    let re = Regex::new(r"mul\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();
+
+    let mut sum = 0;
+    for line in input {
+        for cap in re.captures_iter(line) {
+            let f1 = cap[1].parse::<u32>().unwrap();
+            let f2 = cap[2].parse::<u32>().unwrap();
+            sum += f1 * f2;
+        }
+    }
+    sum
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = [
+            "xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))"
+        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
+        assert_eq!(sum_multiplications(&input), 161);
+    }
+}