Day1 Zig

day1/zig/main.zig

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+const std = @import("std");
+
+const Instruction = enum {
+    L,
+    R,
+};
+
+const MAGIC_NUMBER = 100;
+
+pub fn main() !void {
+    var stdin_buffer: [1024]u8 = undefined;
+    var stdin_reader = std.fs.File.stdin().reader(&stdin_buffer);
+
+    const stdin = &stdin_reader.interface;
+
+    var current: i32 = 50;
+    var task1: u32 = 0;
+    var task2: u32 = 0;
+
+    while (try stdin.takeDelimiter('\n')) |line| {
+        var num = try std.fmt.parseInt(i32, line[1..], 10);
+        switch (line[0]) {
+            'L' => {
+                while (num > 0) : (num -= 1) {
+                    current = @mod(current - 1, MAGIC_NUMBER);
+                    if (current == 0) {
+                        task2 += 1;
+                    }
+                }
+            },
+            'R' => {
+                while (num > 0) : (num -= 1) {
+                    current = @mod(current + 1, MAGIC_NUMBER);
+                    if (current == 0) {
+                        task2 += 1;
+                    }
+                }
+            },
+            else => unreachable,
+        }
+
+        if (current == 0) {
+            task1 += 1;
+        }
+    }
+
+    std.debug.print("{d}\n", .{task1});
+    std.debug.print("{d}\n", .{task2});
+}

day1/zig/sample.txt

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+L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82