day 9 part 1

2023/day09/src/lib.rs

@@ -0,0 +1,73 @@
+use helper::{Day, Variants};
+
+pub fn main() {
+    helper::main::<Day09>(include_str!("../input.txt"));
+}
+
+struct Day09;
+
+helper::define_variants! {
+    day => crate::Day09;
+    part1 {
+        basic => crate::part1;
+    }
+    part2 {
+        basic => crate::part2;
+    }
+}
+
+impl Day for Day09 {
+    fn part1() -> Variants {
+        part1_variants!(construct_variants)
+    }
+
+    fn part2() -> Variants {
+        part2_variants!(construct_variants)
+    }
+}
+
+fn parse(input: &str) -> impl Iterator<Item = Vec<i64>> + '_ {
+    input
+        .lines()
+        .map(|line| line.split_ascii_whitespace().map(|s| s.parse().unwrap()).collect())
+}
+
+fn part1(input: &str) -> u64 {
+    parse(input)
+        .map(|mut values| {
+            let mut last_values = vec![*values.last().unwrap()];
+
+            let mut derive = values.clone();
+
+            while !derive.iter().all(|&n| n == 0) {
+                values.clear();
+                values.extend(derive.windows(2).map(|s| s[1] - s[0]));
+
+                last_values.push(*values.last().unwrap());
+
+                let tmp = derive;
+                derive = values;
+                values = tmp;
+            }
+
+            last_values.into_iter().sum::<i64>()
+        })
+        .sum::<i64>() as u64
+}
+
+fn part2(_input: &str) -> u64 {
+    0
+}
+
+helper::tests! {
+    day09 Day09;
+    part1 {
+        small => 0;
+        default => 0;
+    }
+    part2 {
+        small => 0;
+        default => 0;
+    }
+}
+helper::benchmarks! {}