95 lines
2.3 KiB
Rust
95 lines
2.3 KiB
Rust
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#![allow(non_upper_case_globals)]
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#![allow(unused_imports)]
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use md5::Digest;
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use crate::prelude::*;
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pub type I = &'static str;
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pub type O = String;
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pub type O2 = usize;
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const _cand: [(isize, isize, char); 4] = [(-1, 0, 'U'), (1, 0, 'D'), (0, -1, 'L'), (0, 1, 'R')];
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fn _open_doors ((y, x): (usize, usize), digest: Digest) -> Vec<(usize, usize, char)> {
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let repr = format!("{:x}", digest);
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let access: [char; 4] = repr.chars().take(4).collect_vec().try_into().unwrap();
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_cand.iter()
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.enumerate()
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.filter_map(|(i, &(dy, dx, n))| match (y.checked_add_signed(dy), x.checked_add_signed(dx)) {
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(Some(y), Some(x)) => if y <= 3 && x <= 3 { Some((y, x, n, i)) } else { None },
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_ => None
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})
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.filter(|(_, _, _, idx)| ('b'..='f').contains(&access[*idx]))
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.map(|(a, b, c, _)| (a, b, c))
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.collect()
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}
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fn _digest (pass: &'static str, i: &str) -> Digest {
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let full = format!("{pass}{i}");
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md5::compute(full)
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}
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fn _dfs (cur: (usize, usize), path: &mut String, pass: &'static str) -> bool {
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if cur == (3, 3) { return true; } else {
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let digest = _digest(pass, &path);
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let doors = _open_doors(cur, digest);
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for (ny, nx, p) in doors {
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path.push(p);
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if _dfs((ny, nx), path, pass) {
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return true;
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} else {
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path.pop();
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}
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}
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return false;
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}
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}
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fn _dfs_max (cur: (usize, usize), path: &mut String, pass: &'static str, max: &mut usize) {
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if cur == (3, 3) {
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*max = (*max).max(path.len());
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} else {
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let digest = _digest(pass, &path);
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let doors = _open_doors(cur, digest);
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for (ny, nx, p) in doors {
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path.push(p);
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_dfs_max((ny, nx), path, pass, max);
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path.pop();
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}
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}
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}
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fn _silver (data: I) -> O {
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let mut path = String::new();
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_dfs((0, 0), &mut path, data);
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path
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}
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fn _gold (data: I) -> O2 {
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let mut path = String::new();
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let mut max = 0;
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_dfs_max((0, 0), &mut path, data, &mut max);
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max
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}
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#[cfg(test)]
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mod test {
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use super::*;
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const pass: &'static str = "edjrjqaa";
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#[test]
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fn silver () {
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let ans = _silver(pass);
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assert_eq!(ans, s!("DUDRDLRRRD"))
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}
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#[test]
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fn gold () {
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let ans = _gold(pass);
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assert_eq!(ans, 502)
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}
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}
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