2022-01 in zig

2022/01/second.zig

@@ -0,0 +1,33 @@
+const std = @import("std");
+
+const example = @embedFile("example");
+const input = @embedFile("input");
+
+pub fn main() anyerror!void {
+    try std.testing.expectEqual(solve(example), 45000);
+    const result = try solve(input);
+    try std.io.getStdOut().writer().print("{}\n", .{result});
+}
+
+fn solve(puzzle: []const u8) !u64 {
+    var it = std.mem.split(u8, puzzle, "\n");
+    var top3 = [_]u64{ 0, 0, 0 };
+    var tot: u64 = 0;
+    while (it.next()) |value| {
+        const n = std.fmt.parseInt(u64, value, 10) catch 0;
+        if (n == 0) {
+            for (top3) |*max| {
+                if (tot > max.*) {
+                    // this swapping will keep the array sorted
+                    const prev = max.*;
+                    max.* = tot;
+                    tot = prev;
+                }
+            }
+            tot = 0;
+        } else {
+            tot += n;
+        }
+    }
+    return top3[0] + top3[1] + top3[2];
+}