days 1-3

src/bin/01.rs

@@ -0,0 +1,71 @@
+advent_of_code::solution!(1);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let mut vec_a = Vec::new();
+    let mut vec_b = Vec::new();
+    let mut result = 0;
+
+    for line in input.split('\n').filter(|l| !l.is_empty()) {
+        let vals: Vec<&str> = line.split("   ").collect();
+
+        let a = vals[0].parse::<u32>().unwrap();
+        let b = vals[1].parse::<u32>().unwrap();
+        vec_a.push(a);
+        vec_b.push(b);
+    }
+    vec_a.sort();
+    vec_b.sort();
+
+    for i in 0..vec_a.len() {
+        let diff = vec_a[i].abs_diff(vec_b[i]);
+        result += diff;
+        // println!("Line {}: abs({} - {}) = {}", i+1, vec_a[i], vec_b[i], diff)
+    }
+    // println!("Total {result}");
+    return Some(result);
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let mut vec_a = Vec::new();
+    let mut vec_b = Vec::new();
+    let mut result = 0;
+
+    for line in input.split('\n').filter(|l| !l.is_empty()) {
+        let vals: Vec<&str> = line.split("   ").collect();
+
+        let a = vals[0].parse::<u32>().unwrap();
+        let b = vals[1].parse::<u32>().unwrap();
+        vec_a.push(a);
+        vec_b.push(b);
+    }
+    vec_a.sort();
+    vec_b.sort();
+
+    for i in 0..vec_a.len() {
+        let needle = vec_a[i];
+        let found = vec_b.iter().filter(|&&b| b == needle).count() as u32;
+        let similarity = found * needle;
+        result += similarity;
+
+        // println!("Line {}: {} found {} times = {}, total {}", i + 1, needle, found, similarity, result);
+    }
+    // println!("Total {result}");
+    return Some(result);
+}
+
+#[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, Some(31));
+    }
+}