refactored project structure

src/day03/part03a.rs

@@ -0,0 +1,25 @@
+use iter_first_max::IterFirstMaxExt;
+
+pub fn solve(puzzle: String) -> u64 {
+    let mut solution: u64 = 0;
+
+    puzzle.lines().for_each(|battery_bank| {
+        let batteries = battery_bank
+            .chars()
+            .map(|c| c as u8 - 0x30)
+            .collect::<Vec<u8>>();
+        let (i, biggest_battery) = batteries
+            .iter()
+            .enumerate()
+            .first_max_by_key(|(_, v)| *v)
+            .unwrap();
+        solution += if i < battery_bank.len() - 1 {
+            10 * biggest_battery + batteries[i + 1..].iter().max().unwrap()
+        } else {
+            10 * batteries[..i].iter().max().unwrap() + biggest_battery
+        } as u64;
+    });
+
+    solution
+}
+