Function aoc::year2021::day21::part1

pub fn part1(input: &((usize, usize), (usize, usize))) -> usize

The initial deterministic dice roll total is 6 (1 + 2 + 3) and increases by 9 each turn. An interesting observation is that since the player’s position is always modulo 10, we can also increase the dice total modulo 10, as (a + b) % 10 = (a % 10) + (b % 10).