From b5583ca46effb46d3b9fcc3a7dc04b8a650f401f Mon Sep 17 00:00:00 2001
From: xeals <dev@xeal.me>
Date: Sat, 9 Dec 2023 20:46:40 +1100
Subject: [PATCH] clean day09

---
 src/day09.zig | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/day09.zig b/src/day09.zig
index f4ae708..25438f1 100644
--- a/src/day09.zig
+++ b/src/day09.zig
@@ -46,14 +46,10 @@ fn solve(alloc: mem.Allocator, input: []const u8) !Solution {
         // Extrapolate
         var next: isize = 0;
         var prev: isize = 0;
-        for (seqs.items) |seq| {
-            next += seq[seq.len - 1];
-        }
         for (0..seqs.items.len) |i| {
-            prev = seqs.items[seqs.items.len - i - 1][0] - prev;
-        }
-        for (seqs.items) |seq| {
-            // Clean up
+            const seq = seqs.items[seqs.items.len - i - 1];
+            prev = seq[0] - prev;
+            next += seq[seq.len - 1];
             alloc.free(seq);
         }
         prev_sum += prev;