1 files changed, 68 insertions, 0 deletions
diff --git a/day-2/main.zig b/day-2/main.zig
new file mode 100644
index 0000000..4053caa
--- /dev/null
+++ b/day-2/main.zig
@@ -0,0 +1,68 @@
+const std = @import("std");
+const slurp = @import("util/file.zig").slurp;
+
+var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+const allocator = gpa.allocator();
+
+const Hand = enum(u8) { Rock = 1, Paper = 2, Scissors = 3 };
+const Outcome = enum(u8) { Win = 6, Draw = 3, Lose = 0 };
+
+const KV = struct { @"0": []const u8, @"1": Hand };
+
+const Player_A_KV = std.ComptimeStringMap(Hand, [_]KV{
+    .{ .@"0" = "A", .@"1" = .Rock },
+    .{ .@"0" = "B", .@"1" = .Paper },
+    .{ .@"0" = "C", .@"1" = .Scissors },
+});
+
+const Player_B_KV = std.ComptimeStringMap(Hand, [_]KV{
+    .{ .@"0" = "X", .@"1" = .Rock },
+    .{ .@"0" = "Y", .@"1" = .Paper },
+    .{ .@"0" = "Z", .@"1" = .Scissors },
+});
+
+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 score: u16 = 0;
+
+    while (iter.next()) |line| {
+        if (line.len > 0) {
+            score += match(
+                Player_A_KV.get(&[_]u8{line[0]}).?,
+                Player_B_KV.get(&[_]u8{line[2]}).?,
+            );
+        }
+    }
+
+    std.debug.print("{d}\n", .{score});
+}
+
+fn match(a: Hand, b: Hand) u8 {
+    switch (b) {
+        .Rock => {
+            switch (a) {
+                .Rock => return @enumToInt(b) + @enumToInt(Outcome.Draw),
+                .Paper => return @enumToInt(b) + @enumToInt(Outcome.Lose),
+                .Scissors => return @enumToInt(b) + @enumToInt(Outcome.Win),
+            }
+        },
+        .Paper => {
+            switch (a) {
+                .Rock => return @enumToInt(b) + @enumToInt(Outcome.Win),
+                .Paper => return @enumToInt(b) + @enumToInt(Outcome.Draw),
+                .Scissors => return @enumToInt(b) + @enumToInt(Outcome.Lose),
+            }
+        },
+        .Scissors => {
+            switch (a) {
+                .Rock => return @enumToInt(b) + @enumToInt(Outcome.Lose),
+                .Paper => return @enumToInt(b) + @enumToInt(Outcome.Win),
+                .Scissors => return @enumToInt(b) + @enumToInt(Outcome.Draw),
+            }
+        },
+    }
+}