add day 3

1 files changed, 38 insertions, 0 deletions

diff --git a/day-3/main.zig b/day-3/main.zig
new file mode 100644
index 0000000..4406a79
--- /dev/null
+++ b/day-3/main.zig
@@ -0,0 +1,38 @@
+const std = @import("std");
+const slurp = @import("util/file.zig").slurp;
+const dupl_values = @import("util/mem.zig").dupl_values;
+
+var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+const allocator = gpa.allocator();
+
+pub fn main() !void {
+    const file_buffer = try slurp(allocator, "./input");
+    defer allocator.free(file_buffer);
+
+    var iter = std.mem.split(u8, file_buffer, "\n");
+
+    var count: u16 = 0;
+    while (iter.next()) |line| {
+        const duplicates = try dupl_values(
+            u8,
+            allocator,
+            &[_][]const u8{
+                line[0 .. line.len / 2],
+                line[line.len / 2 ..],
+            },
+        );
+        defer allocator.free(duplicates);
+
+        for (duplicates) |char| {
+            count += char_to_priority(char);
+        }
+    }
+
+    std.debug.print("{d}\n", .{count});
+}
+
+fn char_to_priority(char: u8) u8 {
+    if (char >= 65 and char <= 90)
+        return char - 38;
+    return char - 96;
+}