advent-of-code/2023/day-06/part_one.zig

50 lines
1.1 KiB
Zig

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});
}