09 rust

1 files changed, 4 insertions, 5 deletions

diff --git a/09/rust/src/main.rs b/09/rust/src/main.rs
index 537d38a..f1a52cb 100644
--- a/09/rust/src/main.rs
+++ b/09/rust/src/main.rs
@@ -32,15 +32,14 @@ fn main() {
             }
         }
 
-        history.last_mut().unwrap().push(0);
+        history.last_mut().unwrap().insert(0, 0);
 
         for i in 1..history.len() {
             let i = history.len() - 1 - i;
-            let idx = history[i].len() - 1;
-            let v = history[i][idx] + history[i + 1][idx];
-            history[i].push(v);
+            let v = history[i][0] - history[i + 1][0];
+            history[i].insert(0, v);
         }
-        sum += history[0].last().unwrap();
+        sum += history[0][0];
     }
     println!("{sum}");
 }