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use std::collections::HashSet;
fn get_dir(c: char) -> (i64, i64) {
match c {
'R' => (1, 0),
'L' => (-1, 0),
'U' => (0, 1),
'D' => (0, -1),
_ => panic!("Unexpected char")
}
}
fn follow(lead: (i64, i64), trail: (i64, i64)) -> (i64, i64) {
let max1 = |x: i64| x / (2 - (x%2).abs());
let d = (max1(lead.0 - trail.0), max1(lead.1 - trail.1));
(trail.0 + d.0, trail.1 + d.1)
}
fn step(r: &mut Vec<(i64, i64)>, d: (i64, i64)) {
r[0] = (r[0].0 + d.0, r[0].1 + d.1);
for i in 1..r.len() {
if (r[i].0 - r[i-1].0).abs() > 1 || (r[i].1 - r[i-1].1).abs() > 1 {
r[i] = follow(r[i-1], r[i]);
} else {
break;
}
}
}
pub fn simulate(n: usize) -> HashSet<(i64, i64)> {
let mut r = vec![(0, 0); n];
let mut visited = HashSet::<(i64, i64)>::new();
visited.insert(r[n-1]);
let mut line = String::new();
while std::io::stdin().read_line(&mut line).unwrap() > 0 {
let dir = get_dir(line.chars().nth(0).unwrap());
let l = line[2..line.len()-1].parse::<usize>().unwrap();
for _ in 0..l {
step(&mut r, dir);
visited.insert(r[n-1]);
}
line.clear();
}
visited
}
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