diff --git a/src/day01.zig b/src/day01.zig
index 80e89e2..ba223e9 100644
--- a/src/day01.zig
+++ b/src/day01.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day01.txt");
 
diff --git a/src/day02.zig b/src/day02.zig
index 9e7b6ed..0b9592a 100644
--- a/src/day02.zig
+++ b/src/day02.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day02.txt");
 
diff --git a/src/day03.zig b/src/day03.zig
index 84310cc..63d18c0 100644
--- a/src/day03.zig
+++ b/src/day03.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day03.txt");
 
diff --git a/src/day04.zig b/src/day04.zig
index e944570..09eb9cb 100644
--- a/src/day04.zig
+++ b/src/day04.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day04.txt");
 
diff --git a/src/day05.zig b/src/day05.zig
index 809f9d2..c140c3a 100644
--- a/src/day05.zig
+++ b/src/day05.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day05.txt");
 
diff --git a/src/day06.zig b/src/day06.zig
index 308a012..1850184 100644
--- a/src/day06.zig
+++ b/src/day06.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day06.txt");
 
diff --git a/src/day07.zig b/src/day07.zig
index 9598e17..35ae37a 100644
--- a/src/day07.zig
+++ b/src/day07.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day07.txt");
 
diff --git a/src/day08.zig b/src/day08.zig
index ab2869c..b3ad817 100644
--- a/src/day08.zig
+++ b/src/day08.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day08.txt");
 
diff --git a/src/day09.zig b/src/day09.zig
index 6b78080..ac6d11e 100644
--- a/src/day09.zig
+++ b/src/day09.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day09.txt");
 
diff --git a/src/day10.zig b/src/day10.zig
index c501b71..550f889 100644
--- a/src/day10.zig
+++ b/src/day10.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day10.txt");
 
diff --git a/src/day11.zig b/src/day11.zig
index 913ae0c..5939986 100644
--- a/src/day11.zig
+++ b/src/day11.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day11.txt");
 
diff --git a/src/day12.zig b/src/day12.zig
index 9ee965f..4754a18 100644
--- a/src/day12.zig
+++ b/src/day12.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day12.txt");
 
diff --git a/src/day13.zig b/src/day13.zig
index 7309e9b..b6c3459 100644
--- a/src/day13.zig
+++ b/src/day13.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day13.txt");
 
diff --git a/src/day14.zig b/src/day14.zig
index 194bfdd..719a6ac 100644
--- a/src/day14.zig
+++ b/src/day14.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day14.txt");
 
diff --git a/src/day15.zig b/src/day15.zig
index 0ee0434..255896c 100644
--- a/src/day15.zig
+++ b/src/day15.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day15.txt");
 
diff --git a/src/day16.zig b/src/day16.zig
index f67c08f..92642b7 100644
--- a/src/day16.zig
+++ b/src/day16.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day16.txt");
 
diff --git a/src/day17.zig b/src/day17.zig
index 57fcdb8..1cb647d 100644
--- a/src/day17.zig
+++ b/src/day17.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day17.txt");
 
diff --git a/src/day18.zig b/src/day18.zig
index ea6a8a3..aac11d7 100644
--- a/src/day18.zig
+++ b/src/day18.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day18.txt");
 
diff --git a/src/day19.zig b/src/day19.zig
index 38ba985..90d7d75 100644
--- a/src/day19.zig
+++ b/src/day19.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day19.txt");
 
diff --git a/src/day20.zig b/src/day20.zig
index 245feea..c0e7e11 100644
--- a/src/day20.zig
+++ b/src/day20.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day20.txt");
 
diff --git a/src/day21.zig b/src/day21.zig
index 53c24af..0241c6e 100644
--- a/src/day21.zig
+++ b/src/day21.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day21.txt");
 
diff --git a/src/day22.zig b/src/day22.zig
index 0dfe19b..820d4c8 100644
--- a/src/day22.zig
+++ b/src/day22.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day22.txt");
 
diff --git a/src/day23.zig b/src/day23.zig
index dfffed4..59cf2a9 100644
--- a/src/day23.zig
+++ b/src/day23.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day23.txt");
 
diff --git a/src/day24.zig b/src/day24.zig
index 75a0a00..b74efb3 100644
--- a/src/day24.zig
+++ b/src/day24.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day24.txt");
 
diff --git a/src/day25.zig b/src/day25.zig
index 09cd674..3343eb0 100644
--- a/src/day25.zig
+++ b/src/day25.zig
@@ -7,8 +7,8 @@ const HashMap = std.AutoHashMap;
 const StringHashMap = std.StringHashMap;
 const BitSet = std.DynamicBitSet;
 
-var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
-const gpa = &gpa_impl.allocator;
+const util = @import("util.zig");
+const gpa = util.gpa;
 
 const data = @embedFile("../data/day25.txt");
 
diff --git a/src/util.zig b/src/util.zig
new file mode 100644
index 0000000..09534fa
--- /dev/null
+++ b/src/util.zig
@@ -0,0 +1,13 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const assert = std.debug.assert;
+const print = std.debug.print;
+const ArrayList = std.ArrayList;
+const HashMap = std.AutoHashMap;
+const StringHashMap = std.StringHashMap;
+const BitSet = std.DynamicBitSet;
+
+var gpa_impl = std.heap.GeneralPurposeAllocator(.{}){};
+pub const gpa = &gpa_impl.allocator;
+
+// Add utility functions here