refactored day3 to reduce unneeded mem allocations.

ran rustfmt on all files.

src/day02/utilities.rs

@@ -11,15 +11,14 @@ pub struct Strategy {
     pub you: Play,
 }
 
-pub fn calc_score(input: &Strategy) -> usize{
+pub fn calc_score(input: &Strategy) -> usize {
     //an enum wins if (you-elf)%3 = 1, looses if it = 2
     (match (input.you as i8 - input.elf as i8).rem_euclid(3) {
         1 => 6,
         2 => 0,
         0 => 3,
-        _ => unreachable!("you were {}, elf was {}", input.you as i8, input.elf as i8)
-    //play enum has value corresponding to its score.
-    })+input.you as usize
+        _ => unreachable!("you were {}, elf was {}", input.you as i8, input.elf as i8),
+    }) + input.you as usize //play enum has value corresponding to its score.
 }
 
 #[cfg(test)]
@@ -28,10 +27,10 @@ mod tests {
 
     #[test]
     fn test_calc_score() {
-            let input = Strategy {
-                    elf: Play::Scissors,
-                    you: Play::Scissors
-                };
+        let input = Strategy {
+            elf: Play::Scissors,
+            you: Play::Scissors,
+        };
         assert_eq!(calc_score(&input), 6);
     }
 }