This commit is contained in:
Daniel S. 2020-12-03 14:59:30 +01:00
parent dd6c5aa5c7
commit 0bb5d960e5
2 changed files with 55 additions and 0 deletions

54
src/day3.rs Normal file
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use aoc_runner_derive::{aoc,aoc_generator};
pub struct Forest {
slice: Vec<Vec<bool>>,
}
impl Forest {
fn get(&self, x: usize,y: usize) -> Option<bool> {
self.slice.get(y).map(|line| line.get(x%line.len())).flatten().cloned()
}
}
#[aoc_generator(day3)]
pub fn input_generator(input: &str) -> Forest {
let slice=input.lines().map(|l| l.chars().map(|c| c=='#').collect()).collect();
Forest{
slice
}
}
#[aoc(day3,part1)]
pub fn solve_part1(input: &Forest) -> usize {
let mut sum: usize=0;
let dx=3;
let dy=1;
let mut pos=(0,0);
while let Some(tree) = input.get(pos.0,pos.1) {
if tree {
sum+=1;
}
pos.0+=dx;
pos.1+=dy;
};
sum
}
#[aoc(day3,part2)]
pub fn solve_part2(input: &Forest) -> usize {
let mut prod: usize = 1;
for (dx,dy) in &[(1,1),(3,1),(5,1),(7,1),(1,2)] {
let mut sum: usize=0;
let mut pos=(0,0);
while let Some(tree) = input.get(pos.0,pos.1) {
if tree {
sum+=1;
}
pos.0+=dx;
pos.1+=dy;
};
prod*=sum;
}
prod
}

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use aoc_runner_derive::aoc_lib;
pub mod day1;
pub mod day2;
pub mod day3;
aoc_lib! { year = 2020 }