146 lines
3.4 KiB
Rust
146 lines
3.4 KiB
Rust
mod common;
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use std::collections::HashSet;
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type Input = Vec<(char, i32)>;
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type Answer = usize;
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fn processed_input(input: &str) -> Input {
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input
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.lines()
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.map(|l| {
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let mut args = l.split(' ');
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(
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args.next().unwrap().chars().next().unwrap(),
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args.next().unwrap().parse::<i32>().unwrap(),
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)
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})
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.collect()
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}
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fn part1(input: &Input) -> Answer {
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let mut p: HashSet<(i32, i32)> = HashSet::new();
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let mut h: (i32, i32) = (0, 0);
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let mut t: (i32, i32) = (0, 0);
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let mut m = |x, y, n| {
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for _ in 0..n {
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h.0 += x;
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h.1 += y;
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if t.0.abs_diff(h.0) > 1 && t.1.abs_diff(h.1) > 1 {
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t.0 += (h.0 - t.0) / 2;
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t.1 += (h.1 - t.1) / 2;
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} else if t.0.abs_diff(h.0) > 1 {
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t.0 += (h.0 - t.0) / 2;
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t.1 = h.1;
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} else if t.1.abs_diff(h.1) > 1 {
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t.1 += (h.1 - t.1) / 2;
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t.0 = h.0;
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}
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p.insert(t);
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println!("h: ({}, {}), t: ({}, {})", h.0, h.1, t.0, t.1);
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}
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};
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for i in input {
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println!("{:?}", i);
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match i.0 {
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'L' => m(-1, 0, i.1),
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'R' => m(1, 0, i.1),
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'U' => m(0, -1, i.1),
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'D' => m(0, 1, i.1),
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_ => (),
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}
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}
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p.len()
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}
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fn part2(input: &Input) -> Answer {
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let mut p: HashSet<(i32, i32)> = HashSet::new();
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let mut r: Vec<(i32, i32)> = std::iter::repeat((0, 0)).take(10).collect();
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let mut m = |x, y, n| {
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for _ in 0..n {
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r[0].0 += x;
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r[0].1 += y;
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for s in 1..r.len() {
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if r[s].0.abs_diff(r[s - 1].0) > 1 && r[s].1.abs_diff(r[s - 1].1) > 1 {
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r[s].0 += (r[s - 1].0 - r[s].0) / 2;
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r[s].1 += (r[s - 1].1 - r[s].1) / 2;
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} else if r[s].0.abs_diff(r[s - 1].0) > 1 {
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r[s].0 += (r[s - 1].0 - r[s].0) / 2;
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r[s].1 = r[s - 1].1;
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} else if r[s].1.abs_diff(r[s - 1].1) > 1 {
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r[s].1 += (r[s - 1].1 - r[s].1) / 2;
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r[s].0 = r[s - 1].0;
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}
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}
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p.insert(r[r.len() - 1]);
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println!(
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"h: ({}, {}), t: ({}, {})",
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r[0].0,
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r[0].1,
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r[r.len() - 1].0,
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r[r.len() - 1].1
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);
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}
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};
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for i in input {
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println!("{:?}", i);
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match i.0 {
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'L' => m(-1, 0, i.1),
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'R' => m(1, 0, i.1),
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'U' => m(0, -1, i.1),
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'D' => m(0, 1, i.1),
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_ => (),
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}
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}
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p.len()
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}
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fn main() {
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let input_text = common::day_input(9);
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eprintln!("{}\n\nAbove is your input file.\n\n", input_text);
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let input = processed_input(&input_text);
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common::show_answers(&part1(&input), &part2(&input))
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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const TEST_INPUT: &str = "R 4
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U 4
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L 3
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D 1
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R 4
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D 1
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L 5
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R 2";
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#[test]
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fn test() {
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let input = processed_input(TEST_INPUT);
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assert_eq!(part1(&input), 13);
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assert_eq!(part2(&input), 1);
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}
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const TEST_INPUT2: &str = "R 5
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U 8
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L 8
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D 3
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R 17
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D 10
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L 25
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U 20";
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#[test]
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fn part2_test2() {
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let input2 = processed_input(TEST_INPUT2);
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assert_eq!(part2(&input2), 36);
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}
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}
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