Add solution for 2023 day 06 part 1

2023/day-06/common.zig

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+const std = @import("std");
+const alloc = std.heap.page_allocator;
+
+pub const Races = struct {
+    times: List(u32),
+    distances: List(u32),
+
+    pub fn deinit(self: Races) void {
+        self.times.deinit();
+        self.distances.deinit();
+    }
+};
+
+const List = std.ArrayList;
+
+pub fn parse(data: []const u8) !Races {
+    var lines = std.mem.tokenizeScalar(u8, data, '\n');
+
+    var times = List(u32).init(alloc);
+
+    {
+        const line = lines.next().?;
+        var numbers = std.mem.tokenizeScalar(u8, line, ' ');
+        _ = numbers.next();
+
+        while (numbers.next()) |num_str| {
+            const num = try std.fmt.parseInt(u32, num_str, 10);
+            try times.append(num);
+        }
+    }
+
+    var dists = List(u32).init(alloc);
+
+    {
+        const line = lines.next().?;
+        var numbers = std.mem.tokenizeScalar(u8, line, ' ');
+        _ = numbers.next();
+
+        while (numbers.next()) |num_str| {
+            const num = try std.fmt.parseInt(u32, num_str, 10);
+            try dists.append(num);
+        }
+    }
+
+    const races = .{
+        .times = times,
+        .distances = dists,
+    };
+
+    return races;
+}

2023/day-06/inputs/puzzle.txt

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+Time:        40     82     91     66
+Distance:   277   1338   1349   1063

2023/day-06/inputs/sample.txt

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+Time:      7  15   30
+Distance:  9  40  200

2023/day-06/part_one.zig

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+const std = @import("std");
+const common = @import("common.zig");
+
+const data = @embedFile("inputs/puzzle.txt");
+
+pub fn main() !void {
+    const stdout = std.io.getStdOut().writer();
+
+    const races = try common.parse(data);
+    defer races.deinit();
+
+    var prod: u32 = 1;
+
+    for (races.times.items, 0..) |race_time, i| {
+        const race_record = races.distances.items[i];
+
+        var min: u32 = undefined;
+
+        for (1..race_time) |speed| {
+            const rem_race_time = race_time - speed;
+            const dist = rem_race_time * speed;
+            if (dist > race_record) {
+                min = @intCast(speed);
+                break;
+            }
+        }
+
+        var max: u32 = undefined;
+
+        var speed: u32 = race_time - 1;
+        while (speed > 0) {
+            const rem_race_time = race_time - speed;
+            const dist = rem_race_time * speed;
+
+            if (dist > race_record) {
+                max = speed;
+                break;
+            }
+
+            speed -= 1;
+        }
+
+        const nums_beat = max - min + 1;
+
+        prod *= nums_beat;
+    }
+
+    try stdout.print("{d}\n", .{prod});
+}