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fn slide(lines: Vec<Vec<char>>, vx: i32, vy: i32) -> i32 {
let mut x: i32 = 0;
let mut y: i32 = 0;
let mut hits: i32 = 0;
loop {
if lines[y as usize][x as usize] == '#' {
hits += 1;
}
x += vx;
y += vy;
if y as usize >= lines.len() {
break;
}
if x as usize >= lines[y as usize].len() {
x -= lines[y as usize].len() as i32;
}
}
hits
}
fn slide_everywhere(lines: Vec<Vec<char>>) -> i32 {
let mut hits: i32 = 1;
for (vx, vy) in vec![(1, 1), (3, 1), (5, 1), (7, 1), (1, 2)] {
hits *= slide(lines.clone(), vx, vy);
}
hits
}
fn main() {
let lines: Vec<Vec<char>> = include_str!("../input0.txt")
.trim()
.split("\n")
.map(|s| s.chars().collect())
.collect();
let hits = slide(lines.clone(), 3, 1);
println!("hits: {}", hits);
let hits_everything = slide_everywhere(lines.clone());
println!("hits on the five paths: {}", hits_everything);
}
#[cfg(test)]
mod tests {
use crate::*;
#[test]
fn small_input() {
let lines: Vec<Vec<char>> = include_str!("../test0.txt")
.trim()
.split("\n")
.map(|s| s.chars().collect())
.collect();
assert_eq!(slide(lines, 3, 1), 7);
}
#[test]
fn big_input() {
let lines: Vec<Vec<char>> = include_str!("../input0.txt")
.trim()
.split("\n")
.map(|s| s.chars().collect())
.collect();
assert_eq!(slide(lines, 3, 1), 220);
}
#[test]
fn small_input_all_slopes() {
let lines: Vec<Vec<char>> = include_str!("../test0.txt")
.trim()
.split("\n")
.map(|s| s.chars().collect())
.collect();
assert_eq!(slide_everywhere(lines), 336);
}
}
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