day1 part 1

src/main.rs

@@ -1,3 +1,46 @@
+use itertools::Itertools;
+use std::fs::read_to_string;
+
 fn main() {
-    println!("Hello, world!");
+    let input = read_to_string("input/day01.txt").unwrap();
+    let part1 = part1(&input);
+    println!("part1: {}", part1);
+}
+
+type Int = i32;
+
+fn part1(input: &str) -> Int {
+    let (mut l, mut r) = input
+        .trim()
+        .lines()
+        .map(|line| line.split_ascii_whitespace().collect_tuple().unwrap())
+        .map(|(x, y)| (x.parse::<Int>().unwrap(), y.parse::<Int>().unwrap()))
+        .fold((vec![], vec![]), |(mut v1, mut v2), (a, b)| {
+            v1.push(a);
+            v2.push(b);
+            (v1, v2)
+        });
+
+    l.sort();
+    r.sort();
+
+    l.into_iter()
+        .zip(r.into_iter())
+        .map(|(l, r)| (l - r).abs())
+        .sum()
+}
+
+#[cfg(test)]
+const TEST_INPUT: &str = r"
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3
+";
+
+#[test]
+fn test() {
+    assert_eq!(part1(TEST_INPUT), 11);
 }