Day 2 part 1

day-2/main.zig

@@ -0,0 +1,62 @@
+const std = @import("std");
+
+pub fn define_direction(num1: i32, num2: i32) i8 {
+    if (num1 > num2) {
+        return -1;
+    } else if (num2 > num1) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+pub fn main() !void {
+    var file = try std.fs.cwd().openFile("input.txt", .{});
+    defer file.close();
+
+    var buf_reader = std.io.bufferedReader(file.reader());
+    var in_stream = buf_reader.reader();
+
+    var safe_reports: u32 = 0;
+
+    var buf: [2048]u8 = undefined;
+    while (try in_stream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
+        var is_safe = true;
+        var first_round = true;
+        var last_num: i32 = 0;
+        var defined_direction = false;
+        var direction: i8 = 0;
+        var tokAny = std.mem.tokenizeAny(u8, line, " ");
+        while (tokAny.next()) |num| {
+            std.debug.print("{s} ", .{num});
+            const n = try std.fmt.parseInt(i32, num, 10);
+            if (first_round) {
+                last_num = n;
+                first_round = false;
+                continue;
+            }
+            if (@abs(last_num - n) > 3) {
+                is_safe = false;
+                break;
+            }
+
+            const current_direction = define_direction(last_num, n);
+
+            if (!defined_direction) {
+                direction = current_direction;
+                defined_direction = true;
+            }
+            if (current_direction != direction or current_direction == 0) {
+                is_safe = false;
+                break;
+            }
+            last_num = n;
+        }
+        std.debug.print("\n", .{});
+
+        if (is_safe) {
+            safe_reports += 1;
+        }
+    }
+    std.debug.print("{}", .{safe_reports});
+}