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advent-of-code/2016/rust/src/main.rs

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use std::collections::HashSet;
use std::io;
use std::io::Read;
use std::f32::consts::PI;
fn solve(input: &str) -> String {
let mut turtle = (-PI / 2.0, (0, 0));
let mut visited: HashSet<(i32, i32)> = HashSet::new();
for step in input.split(", ") {
let mut chars = step.chars();
let dir = chars.next().unwrap();
let blocks = chars.collect::<String>().parse::<i32>().unwrap();
turtle.0 += match dir {
'R' => PI / 2.0,
'L' => -PI / 2.0,
_ => {
unreachable!();
}
};
for _ in 0..blocks {
let movement = turtle.0.sin_cos();
(turtle.1).0 += movement.1 as i32;
(turtle.1).1 += movement.0 as i32;
if visited.contains(&turtle.1) {
return ((turtle.1).0.abs() + (turtle.1).1.abs()).to_string()
} else {
visited.insert(turtle.1);
}
}
}
((turtle.1).0.abs() + (turtle.1).1.abs()).to_string()
}
#[test]
fn test_solve() {
// assert_eq!(solve("R2, L3"), "5".to_string());
// assert_eq!(solve("R2, R2, R2"), "2".to_string());
// assert_eq!(solve("R5, L5, R5, R3"), "12".to_string());
assert_eq!(solve("R8, R4, R4, R8"), "4".to_string());
}
fn main() {
let mut input = String::new();
io::stdin().read_to_string(&mut input).ok();
println!("{}", solve(&input));
}