Solve Day 1 Part 1

Author: destinationunknown

data/examples/01.txt

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3

src/bin/01.rs

@@ -0,0 +1,46 @@
+advent_of_code::solution!(1);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    // read input into two lists
+    let (mut a, mut b): (Vec<u32>, Vec<u32>) = input
+        .lines()
+        .filter_map(|line| {
+            let mut parts = line.split_whitespace();
+            let first = parts.next()?.parse::<u32>().ok()?;
+            let second = parts.next()?.parse::<u32>().ok()?;
+            Some((first, second))
+        })
+        .unzip();
+
+    a.sort();
+    b.sort();
+
+    let sum_diff: u32 = a
+        .iter()
+        .zip(b.iter())
+        .map(|(x, y)| if x > y { x - y } else { y - x })
+        .sum();
+
+    Some(sum_diff)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(11));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, None);
+    }
+}