結果
問題 |
No.1424 Ultrapalindrome
|
ユーザー |
|
提出日時 | 2022-11-07 11:27:34 |
言語 | Rust (1.83.0 + proconio) |
結果 |
WA
|
実行時間 | - |
コード長 | 2,962 bytes |
コンパイル時間 | 15,061 ms |
コンパイル使用メモリ | 378,452 KB |
実行使用メモリ | 16,088 KB |
最終ジャッジ日時 | 2024-07-20 19:48:01 |
合計ジャッジ時間 | 18,330 ms |
ジャッジサーバーID (参考情報) |
judge5 / judge1 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 28 WA * 1 |
コンパイルメッセージ
warning: unused variable: `n` --> src/main.rs:21:9 | 21 | let n = paths.len(); | ^ help: if this is intentional, prefix it with an underscore: `_n` | = note: `#[warn(unused_variables)]` on by default
ソースコード
use std::collections::{VecDeque, HashSet}; const INF: usize = 1usize << 60; fn tree_diameter(paths: &Vec<Vec<(usize, usize)>>) -> (usize, usize, usize) { fn calc(paths: &Vec<Vec<(usize, usize)>>, start: usize) -> Vec<usize> { let n = paths.len(); let mut costs = vec![INF; n]; costs[start] = 0usize; let mut deq = VecDeque::new(); deq.push_back(start); while let Some(u) = deq.pop_front() { for &(v, cost) in paths[u].iter() { if costs[v] < INF { continue; } costs[v] = costs[v].min(costs[u] + cost); deq.push_back(v); } } costs } let n = paths.len(); let costs = calc(paths, 0); let idx = costs.into_iter().enumerate().max_by_key(|&(_, c)| c).unwrap().0; let costs = calc(paths, idx); let ridx = costs.into_iter().enumerate().max_by_key(|&(_, c)| c).unwrap(); // start_point, end_point, cost (idx, ridx.0, ridx.1) } fn get_leaves(cur: usize, paths: &Vec<Vec<(usize, usize)>>) -> Vec<bool> { let n = paths.len(); let mut ret = vec![true; n]; let mut checked = vec![false; n]; checked[cur] = true; let mut deque = VecDeque::new(); deque.push_back(cur); while let Some(u) = deque.pop_front() { for &(v, _) in paths[u].iter() { if checked[v] { continue; } checked[v] = true; ret[u] = false; deque.push_back(v); } } ret[cur] = true; ret } fn get_dists(cur: usize, paths: &Vec<Vec<(usize, usize)>>) -> Vec<usize> { let n = paths.len(); let mut ret = vec![INF; n]; ret[cur] = 0; let mut deque = VecDeque::new(); deque.push_back(cur); while let Some(u) = deque.pop_front() { for &(v, _) in paths[u].iter() { if ret[v] < INF { continue; } ret[v] = ret[u] + 1; deque.push_back(v); } } ret } fn main() { let mut n = String::new(); std::io::stdin().read_line(&mut n).ok(); let n: usize = n.trim().parse().unwrap(); let mut paths = vec![vec![]; n]; for _ in 0..n-1 { let mut ab = String::new(); std::io::stdin().read_line(&mut ab).ok(); let ab: Vec<usize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect(); let a = ab[0]-1; let b = ab[1]-1; paths[a].push((b, 1)); paths[b].push((a, 1)); } let (left, right, _) = tree_diameter(&paths); let leaves = get_leaves(left, &paths); let l_dists = get_dists(left, &paths); let r_dists = get_dists(right, &paths); let mut result = HashSet::new(); for i in 0..n { if !leaves[i] { continue; } if i != left { result.insert(l_dists[i]); } if i != right { result.insert(r_dists[i]); } } if result.len() == 1 { println!("Yes"); } else { println!("No"); } }