09

1 files changed, 3 insertions, 3 deletions

diff --git a/09/main.cpp b/09/main.cpp
index a83b55d..9e959f3 100644
--- a/09/main.cpp
+++ b/09/main.cpp
@@ -25,12 +25,12 @@ int main() {
 			}
 		}
 
-		history.back().push_back(0);
+		history.back().insert(history.back().begin(), 0);
 		long last_v = 0;
 		for (auto i = 1u; i < history.size(); i++) {
 			auto k = history.size() - 1 - i;
-			last_v = history[k].back() + history[k + 1].back();
-			history[k].push_back(last_v);
+			last_v = history[k][0] - history[k + 1][0];
+			history[k].insert(history[k].begin(), last_v);
 		}
 
 		sum += last_v;