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-rw-r--r--2021/02/example6
-rw-r--r--2021/02/first.zig31
-rw-r--r--2021/02/second.zig35
3 files changed, 72 insertions, 0 deletions
diff --git a/2021/02/example b/2021/02/example
new file mode 100644
index 0000000..b7172ac
--- /dev/null
+++ b/2021/02/example
@@ -0,0 +1,6 @@
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2
diff --git a/2021/02/first.zig b/2021/02/first.zig
new file mode 100644
index 0000000..774cb53
--- /dev/null
+++ b/2021/02/first.zig
@@ -0,0 +1,31 @@
+const std = @import("std");
+
+const example = @embedFile("example");
+const input = @embedFile("input");
+
+pub fn main() anyerror!void {
+ const result = try solve(input);
+ try std.io.getStdOut().writer().print("{}\n", .{result});
+}
+
+fn solve(puzzle: []const u8) !u64 {
+ var it = std.mem.tokenize(u8, puzzle, "\n");
+ var pos: u64 = 0;
+ var depth: u64 = 0;
+ while (it.next()) |line| {
+ var it2 = std.mem.tokenize(u8, line, " ");
+ const step = it2.next() orelse unreachable;
+ const n: u64 = std.fmt.parseInt(u64, it2.next().?, 10) catch unreachable;
+ switch (step[0]) {
+ 'f' => pos += n,
+ 'd' => depth += n,
+ 'u' => depth -= n,
+ else => unreachable,
+ }
+ }
+ return pos * depth;
+}
+
+test "solve" {
+ try std.testing.expectEqual(solve(example), 150);
+}
diff --git a/2021/02/second.zig b/2021/02/second.zig
new file mode 100644
index 0000000..3126118
--- /dev/null
+++ b/2021/02/second.zig
@@ -0,0 +1,35 @@
+const std = @import("std");
+
+const example = @embedFile("example");
+const input = @embedFile("input");
+
+pub fn main() anyerror!void {
+ const result = try solve(input);
+ try std.io.getStdOut().writer().print("{}\n", .{result});
+}
+
+fn solve(puzzle: []const u8) !u64 {
+ var it = std.mem.tokenize(u8, puzzle, "\n");
+ var aim: u64 = 0;
+ var pos: u64 = 0;
+ var depth: u64 = 0;
+ while (it.next()) |line| {
+ var it2 = std.mem.tokenize(u8, line, " ");
+ const step = it2.next() orelse unreachable;
+ const n: u64 = std.fmt.parseInt(u64, it2.next().?, 10) catch unreachable;
+ switch (step[0]) {
+ 'f' => {
+ pos += n;
+ depth += n * aim;
+ },
+ 'd' => aim += n,
+ 'u' => aim -= n,
+ else => unreachable,
+ }
+ }
+ return pos * depth;
+}
+
+test "solve" {
+ try std.testing.expectEqual(solve(example), 900);
+}