AdventOfCode/Rust/2020/03.rs

35 lines
750 B
Rust

#![feature(test)]
type Input = Vec<String>;
fn setup(input: &str) -> Input {
input.lines().map(|s| s.to_string()).collect()
}
fn cnt_slope(input: &Input, dx: u64, dy: u64) -> u64 {
let mut out = 0;
let mut x = 0;
let mut y = 0;
while y < input.len() {
if input[y].chars().nth(x % input[y].len()).unwrap() == '#' {
out += 1;
}
x += dx as usize;
y += dy as usize;
}
out
}
fn part1(input: &Input) -> String {
cnt_slope(input, 3, 1).to_string()
}
fn part2(input: &Input) -> String {
[(1, 1), (3, 1), (5, 1), (7, 1), (1, 2)]
.iter()
.map(|&(dx, dy)| cnt_slope(input, dx, dy))
.product::<u64>()
.to_string()
}
aoc::main!(2020, 3, ex: 1);