1 files changed, 61 insertions, 0 deletions
diff --git a/src/02/main.zig b/src/02/main.zig
new file mode 100644
index 0000000..e965c95
--- /dev/null
+++ b/src/02/main.zig
@@ -0,0 +1,61 @@
+const std = @import("std");
+const aoc = @import("aoc");
+
+const Entry = struct { a: u16, b: u16, char: u8, pass: []u8 };
+
+fn freeEntries(allocator: std.mem.Allocator, entries: *const std.ArrayList(Entry)) void {
+    for (entries.items) |item|
+        allocator.free(item.pass);
+    entries.deinit();
+}
+
+fn parse(allocator: std.mem.Allocator, input: []u8) !std.ArrayList(Entry) {
+    var entries = std.ArrayList(Entry).init(allocator);
+    errdefer freeEntries(allocator, &entries);
+
+    var lineit = std.mem.tokenize(u8, input, "\n");
+    while (lineit.next()) |line| {
+        var entry: Entry = undefined;
+        var it = std.mem.tokenize(u8, line, " -");
+        entry.a = try std.fmt.parseInt(u16, it.next().?, 10);
+        entry.b = try std.fmt.parseInt(u16, it.next().?, 10);
+        entry.char = it.next().?[0];
+        entry.pass = try allocator.dupe(u8, it.next().?);
+        try entries.append(entry);
+    }
+
+    return entries;
+}
+
+fn part1(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
+    _ = args;
+
+    const entries = try parse(allocator, input);
+    defer freeEntries(allocator, &entries);
+
+    var valid: u32 = 0;
+    for (entries.items) |entry| {
+        var count: u16 = 0;
+        for (entry.pass) |c| count += @boolToInt(c == entry.char);
+        valid += @boolToInt(count >= entry.a and count <= entry.b);
+    }
+
+    return try std.fmt.allocPrint(allocator, "{d}", .{valid});
+}
+
+fn part2(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
+    _ = args;
+
+    const entries = try parse(allocator, input);
+    defer freeEntries(allocator, &entries);
+
+    var valid: u32 = 0;
+    for (entries.items) |entry| {
+        valid += @boolToInt((entry.pass[entry.a - 1] == entry.char) !=
+            (entry.pass[entry.b - 1] == entry.char));
+    }
+
+    return try std.fmt.allocPrint(allocator, "{d}", .{valid});
+}
+
+pub const main = aoc.main(part1, part2, .{ "603", "404" });