day1 solution 1

1 files changed, 42 insertions, 0 deletions

diff --git a/src/bin/day1.rs b/src/bin/day1.rs
new file mode 100644
index 0000000..d0c9bae
--- /dev/null
+++ b/src/bin/day1.rs
@@ -0,0 +1,42 @@
+static DAY: u8 = 1;
+
+fn main() {
+    let input = advent::read_lines(DAY);
+    println!("{DAY}a: {}", list_distance(&input));
+    println!("{DAY}b: {}", 0);
+}
+
+fn list_distance(numbers: &[String]) -> u32 {
+    let mut list1 = Vec::new();
+    let mut list2 = Vec::new();
+    for pair in numbers {
+        let (number1, number2) = pair.split_once("   ").unwrap();
+        list1.push(number1.parse::<u32>().unwrap());
+        list2.push(number2.parse::<u32>().unwrap());
+    }
+    list1.sort();
+    list2.sort();
+
+    list1.iter()
+         .enumerate()
+         .map(|(i, number1)| number1.abs_diff(list2[i]))
+         .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = [
+            "3   4",
+            "4   3",
+            "2   5",
+            "1   3",
+            "3   9",
+            "3   3",
+        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
+        assert_eq!(list_distance(&input), 11);
+    }
+}