feat(22/2024): calculate prices and diffs

src/solutions/year2024/day22.rs

@@ -1,4 +1,5 @@
 use crate::solutions::Solution;
+use itertools::Itertools;
 
 pub struct Day22;
 
@@ -16,15 +17,26 @@ impl Solution for Day22 {
             .to_string()
     }
 
-    fn part_two(&self, _input: &str) -> String {
+    fn part_two(&self, input: &str) -> String {
+        let _diffs: Vec<Vec<i8>> = input
+            .lines()
+            .map(|line| {
+                let initial: usize = line.parse().unwrap();
+                let secrets = self.next_secrets(initial, 2000);
+                let prices = self.prices(secrets);
+
+                self.diffs(prices)
+            })
+            .collect();
+
         String::from("0")
     }
 }
 
 impl Day22 {
     fn next_secrets(&self, initial: usize, number_of_secrets: usize) -> Vec<usize> {
         let mut secret = initial;
-        let mut next_secrets = Vec::new();
+        let mut next_secrets = vec![initial];
 
         for _ in 0..number_of_secrets {
             secret = self.mix_and_prune(secret, |s| s * 64);
@@ -40,38 +52,68 @@ impl Day22 {
     fn mix_and_prune(&self, current: usize, calculations: fn(usize) -> usize) -> usize {
         (current ^ calculations(current)) % 16777216
     }
+
+    fn prices(&self, secrets: Vec<usize>) -> Vec<i8> {
+        secrets.iter().map(|secret| (secret % 10) as i8).collect()
+    }
+
+    fn diffs(&self, secrets: Vec<i8>) -> Vec<i8> {
+        secrets.iter().tuple_windows().map(|(a, b)| b - a).collect()
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use crate::solutions::year2024::day22::Day22;
     use crate::solutions::Solution;
 
-    const EXAMPLE: &str = r#"1
+    const PART_ONE_EXAMPLE: &str = r#"1
 10
 100
 2024"#;
 
     #[test]
     fn part_one_example() {
-        assert_eq!("37327623", Day22.part_one(EXAMPLE));
+        assert_eq!("37327623", Day22.part_one(PART_ONE_EXAMPLE));
+    }
+
+    const PART_TWO_EXAMPLE: &str = r#"1
+2
+3
+2024"#;
+
+    #[test]
+    #[ignore]
+    fn part_two_example() {
+        assert_eq!("23", Day22.part_two(PART_TWO_EXAMPLE));
     }
 
     #[test]
     fn next_secrets() {
-        let tmp = Day22.next_secrets(123, 10);
-        let mut result = tmp.iter();
-
-        assert_eq!(Some(&15887950), result.next());
-        assert_eq!(Some(&16495136), result.next());
-        assert_eq!(Some(&527345), result.next());
-        assert_eq!(Some(&704524), result.next());
-        assert_eq!(Some(&1553684), result.next());
-        assert_eq!(Some(&12683156), result.next());
-        assert_eq!(Some(&11100544), result.next());
-        assert_eq!(Some(&12249484), result.next());
-        assert_eq!(Some(&7753432), result.next());
-        assert_eq!(Some(&5908254), result.next());
-        assert_eq!(None, result.next());
+        let secrets = Day22.next_secrets(123, 10);
+        let mut iter = secrets.iter();
+
+        assert_eq!(Some(&123), iter.next());
+        assert_eq!(Some(&15887950), iter.next());
+        assert_eq!(Some(&16495136), iter.next());
+        assert_eq!(Some(&527345), iter.next());
+        assert_eq!(Some(&704524), iter.next());
+        assert_eq!(Some(&1553684), iter.next());
+        assert_eq!(Some(&12683156), iter.next());
+        assert_eq!(Some(&11100544), iter.next());
+        assert_eq!(Some(&12249484), iter.next());
+        assert_eq!(Some(&7753432), iter.next());
+        assert_eq!(Some(&5908254), iter.next());
+        assert_eq!(None, iter.next());
+    }
+
+    #[test]
+    fn prices_and_diffs() {
+        let secrets = Day22.next_secrets(123, 9);
+        let prices = Day22.prices(secrets);
+        assert_eq!(vec![3, 0, 6, 5, 4, 4, 6, 4, 4, 2], prices);
+
+        let diffs = Day22.diffs(prices);
+        assert_eq!(vec![-3, 6, -1, -1, 0, 2, -2, 0, -2], diffs);
     }
 }