it works

src/day01.zig

@@ -8,6 +8,30 @@ pub fn main() !void {
     std.debug.print("Hello, {s}!\n", .{"World"});
 }
 
+fn solve(str_input: []const u8, allocator: std.mem.Allocator) !u32 {
+    const left, const right = try get_list(str_input, allocator);
+    defer {
+        left.deinit();
+        right.deinit();
+    }
+
+    std.mem.sort(u32, left.items, {}, comptime std.sort.asc(u32));
+    std.mem.sort(u32, right.items, {}, comptime std.sort.asc(u32));
+
+    try expect(std.mem.eql(u32, left.items, &[_]u32{ 1, 2, 3, 3, 3, 4 }));
+    try expect(std.mem.eql(u32, right.items, &[_]u32{ 3, 3, 3, 4, 5, 9 }));
+
+    try expect(left.items.len == right.items.len);
+    var total: u32 = 0;
+    for (0..left.items.len) |index| {
+        const left_item = left.items[index];
+        const right_item = right.items[index];
+        total += (right_item - left_item);
+    }
+
+    return total;
+}
+
 fn parse_line(line: []const u8) !struct { u32, u32 } {
     var parts = std.mem.tokenizeScalar(u8, line, ' ');
     const left = try std.fmt.parseInt(u32, parts.next().?, 10);
@@ -33,14 +57,8 @@ const test_allocator = std.testing.allocator;
 const input = "3   4\n4   3\n2   5\n1   3\n3   9\n3   3";
 
 test "day01_given_example" {
-    const left, const right = try get_list(input, test_allocator);
-    defer {
-        left.deinit();
-        right.deinit();
-    }
-    // const expected_distances = [_]u32{ 2, 1, 0, 1, 2, 5 };
-    // const expected_distance_total: u32 = 11;
-    try expect(false);
+    const total = try solve(input, test_allocator);
+    try expect(total == 11);
 }
 
 test "day01_parse_line" {