day5: performance: don't iterate to position just do arithemtic

2023-12-06 11:07:40 -08:00
parent 6d1174e2db
commit 0665e109af
1 changed files with 1 additions and 4 deletions
--- a/5/src/main.rs
+++ b/5/src/main.rs
@@ -163,10 +163,7 @@ impl From<&str> for AlmanacMapping {
 impl AlmanacMapping {
    fn lookup(&self, key: u64) -> Option<u64> {
        if self.source_range.contains(&key) {
-            match self.source_range.clone().position(|x| x == key) {
-                Some(i) => self.dest_range.clone().nth(i),
-                None => None,
-            }
+            Some(self.dest_range.start + (key - self.source_range.start))
        } else {
            None
        }