day-9 done and clippied

2023/day-9/Cargo.toml

@@ -10,3 +10,4 @@ repository.workspace = true
 [dependencies]
 nom.workspace = true
 itertools.workspace = true
+rstest = {workspace = true}

2023/day-9/src/part1.rs

@@ -1,20 +1,62 @@
 #![warn(clippy::all, clippy::pedantic)]
 
+use nom::{character::complete, multi::separated_list1, IResult};
+use std::{iter::successors, ops::Not};
+
+/// day 9 part 1 of aoc 2023
+///
+/// # Arguments
+/// - input the input for today's puzzle
+///
+/// # Panics
+/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
+/// usize
 #[must_use]
-pub fn part1 (_input: &str) -> String {
-    "Not Finished".to_string()
+pub fn part1(input: &str) -> String {
+    let (_, report) = parse_input(input).expect("should have valid input for aoc");
+    report.iter().map(|x| get_next(x)).sum::<i64>().to_string()
+}
+
+fn get_next(array: &[i64]) -> i64 {
+    let array = Vec::from(array);
+    successors(Some(array), |a| {
+        a.iter()
+            .all(|x| x == &0)
+            .not()
+            .then_some(a.windows(2).map(|a| a[1] - a[0]).collect::<Vec<_>>())
+    })
+    .map(|x| *x.last().unwrap())
+    .sum()
+}
+
+fn parse_input(input: &str) -> IResult<&str, Vec<Vec<i64>>> {
+    separated_list1(
+        complete::line_ending,
+        separated_list1(complete::space1, complete::i64),
+    )(input)
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
+    use rstest::rstest;
 
-    const INPUT: &str = "";
+    #[rstest]
+    #[case(vec![0,3,6,9,12,15], 18)]
+    #[case(vec![1,3,6,10,15,21], 28)]
+    #[case(vec![10,13,16,21,30,45], 68)]
+    fn part1_next(#[case] array: Vec<i64>, #[case] expected: i64) {
+        assert_eq!(get_next(&array), expected);
+    }
+
+    const INPUT: &str = "0 3 6 9 12 15
+1 3 6 10 15 21
+10 13 16 21 30 45";
 
     #[test]
     fn part1_works() {
         let result = part1(INPUT);
-        assert_eq!(result, "Not Finished".to_string());
+        assert_eq!(result, "114".to_string());
     }
 }
 

2023/day-9/src/part2.rs

@@ -1,20 +1,64 @@
 #![warn(clippy::all, clippy::pedantic)]
 
+use nom::{character::complete, multi::separated_list1, IResult};
+use std::{iter::successors, ops::Not};
+
+/// day 9 part 2 of aoc 2023
+///
+/// # Arguments
+/// - input the input for today's puzzle
+///
+/// # Panics
+/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
+/// usize
 #[must_use]
-pub fn part2 (_input: &str) -> String {
-    "Not Finished".to_string()
+pub fn part2(input: &str) -> String {
+    let (_, report) = parse_input(input).expect("should have valid input for aoc");
+    report.iter().map(|x| get_next(x)).sum::<i64>().to_string()
+}
+
+fn get_next(array: &[i64]) -> i64 {
+    let array = Vec::from(array);
+    let mut a = successors(Some(array.clone()), |a| {
+        a.iter()
+            .all(|x| x == &0)
+            .not()
+            .then_some(a.windows(2).map(|a| a[1] - a[0]).collect::<Vec<_>>())
+    })
+    .map(|x| *x.first().unwrap())
+    .collect::<Vec<_>>();
+    a.reverse();
+    a.iter().fold(0, |acc, x| x - acc)
+}
+
+fn parse_input(input: &str) -> IResult<&str, Vec<Vec<i64>>> {
+    separated_list1(
+        complete::line_ending,
+        separated_list1(complete::space1, complete::i64),
+    )(input)
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
+    use rstest::rstest;
 
-    const INPUT: &str = "";
+    #[rstest]
+    #[case(vec![0,3,6,9,12,15], -3)]
+    #[case(vec![1,3,6,10,15,21], 0)]
+    #[case(vec![10,13,16,21,30,45], 5)]
+    fn part2_next(#[case] array: Vec<i64>, #[case] expected: i64) {
+        assert_eq!(get_next(&array), expected);
+    }
+
+    const INPUT: &str = "0 3 6 9 12 15
+1 3 6 10 15 21
+10 13 16 21 30 45";
 
     #[test]
     fn part2_works() {
         let result = part2(INPUT);
-        assert_eq!(result, "Not Finished".to_string());
+        assert_eq!(result, "2".to_string());
     }
 }