結果

問題 No.2677 Minmax Independent Set
ユーザー koba-e964koba-e964
提出日時 2024-03-16 09:06:12
言語 Rust
(1.77.0 + proconio)
結果
AC  
実行時間 477 ms / 2,000 ms
コード長 5,684 bytes
コンパイル時間 15,006 ms
コンパイル使用メモリ 379,428 KB
実行使用メモリ 139,392 KB
最終ジャッジ日時 2024-09-30 03:54:17
合計ジャッジ時間 29,312 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge3
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
6,820 KB
testcase_01 AC 2 ms
6,816 KB
testcase_02 AC 2 ms
6,820 KB
testcase_03 AC 2 ms
6,820 KB
testcase_04 AC 2 ms
6,820 KB
testcase_05 AC 436 ms
91,624 KB
testcase_06 AC 427 ms
92,416 KB
testcase_07 AC 399 ms
92,928 KB
testcase_08 AC 390 ms
94,208 KB
testcase_09 AC 383 ms
96,512 KB
testcase_10 AC 324 ms
93,440 KB
testcase_11 AC 322 ms
93,440 KB
testcase_12 AC 309 ms
139,392 KB
testcase_13 AC 383 ms
108,288 KB
testcase_14 AC 362 ms
109,312 KB
testcase_15 AC 380 ms
118,912 KB
testcase_16 AC 451 ms
88,576 KB
testcase_17 AC 457 ms
88,576 KB
testcase_18 AC 282 ms
57,216 KB
testcase_19 AC 327 ms
67,200 KB
testcase_20 AC 88 ms
25,088 KB
testcase_21 AC 379 ms
74,240 KB
testcase_22 AC 20 ms
8,320 KB
testcase_23 AC 2 ms
5,248 KB
testcase_24 AC 1 ms
5,248 KB
testcase_25 AC 1 ms
5,248 KB
testcase_26 AC 1 ms
5,248 KB
testcase_27 AC 2 ms
5,248 KB
testcase_28 AC 309 ms
94,208 KB
testcase_29 AC 398 ms
119,808 KB
testcase_30 AC 1 ms
5,248 KB
testcase_31 AC 1 ms
5,248 KB
testcase_32 AC 1 ms
5,248 KB
testcase_33 AC 1 ms
5,248 KB
testcase_34 AC 1 ms
5,248 KB
testcase_35 AC 1 ms
5,248 KB
testcase_36 AC 1 ms
5,248 KB
testcase_37 AC 2 ms
5,248 KB
testcase_38 AC 2 ms
5,248 KB
testcase_39 AC 3 ms
5,248 KB
testcase_40 AC 4 ms
5,248 KB
testcase_41 AC 8 ms
5,248 KB
testcase_42 AC 17 ms
7,296 KB
testcase_43 AC 37 ms
12,416 KB
testcase_44 AC 84 ms
22,912 KB
testcase_45 AC 203 ms
43,904 KB
testcase_46 AC 456 ms
85,780 KB
testcase_47 AC 474 ms
87,040 KB
testcase_48 AC 477 ms
87,040 KB
testcase_49 AC 455 ms
87,296 KB
testcase_50 AC 102 ms
36,992 KB
testcase_51 AC 7 ms
5,248 KB
testcase_52 AC 257 ms
78,336 KB
testcase_53 AC 232 ms
72,448 KB
testcase_54 AC 6 ms
5,248 KB
testcase_55 AC 393 ms
94,336 KB
testcase_56 AC 392 ms
94,292 KB
testcase_57 AC 386 ms
94,248 KB
testcase_58 AC 384 ms
94,336 KB
testcase_59 AC 393 ms
94,164 KB
testcase_60 AC 186 ms
87,596 KB
testcase_61 AC 236 ms
88,408 KB
testcase_62 AC 201 ms
96,856 KB
testcase_63 AC 238 ms
118,116 KB
権限があれば一括ダウンロードができます
コンパイルメッセージ
warning: field `acc` is never read
  --> src/main.rs:45:5
   |
44 | struct MonoidalReroot<M: Monoid> {
   |        -------------- field in this struct
45 |     acc: Vec<Vec<M::E>>,
   |     ^^^
   |
   = note: `#[warn(dead_code)]` on by default

ソースコード

diff # 

// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes.by_ref().map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr,) => {};
    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) };
    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };
    ($next:expr, usize1) => (read_value!($next, usize) - 1);
    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
}

trait Monoid {
    type V;
    type E: Clone;
    fn add(a: &Self::E, b: &Self::E) -> Self::E;
    fn e() -> Self::E;
    fn put_edge(a: &Self::V, eidx: EIdx) -> Self::E;
    fn put_vertex(a: &Self::E, vidx: usize) -> Self::V;
}

// Ported from https://trap.jp/post/1702/
struct MonoidalReroot<M: Monoid> {
    acc: Vec<Vec<M::E>>,
    acc_rev: Vec<Vec<M::E>>,
}
type EIdx = usize;

impl<M: Monoid> MonoidalReroot<M> {
    pub fn new(g: &[Vec<(usize, EIdx)>]) -> Self {
        let n = g.len();
        let mut acc = vec![vec![]; n];
        let mut acc_rev = vec![vec![]; n];
        let mut ch = vec![vec![]; n];
        for i in 0..n {
            acc[i] = vec![M::e(); g[i].len() + 1];
            acc_rev[i] = vec![M::e(); g[i].len() + 1];
        }
        Self::dfs1(0, n, &g, &mut ch);
        for i in 0..n {
            let l = ch[i].len();
            ch[i].sort_unstable_by_key(|&(eidx, _)| eidx);
            for j in 0..l {
                let val = M::add(&acc[i][j], &ch[i][j].1);
                acc[i][j + 1] = val;
            }
            for j in (0..l).rev() {
                let val = M::add(&acc_rev[i][j + 1], &ch[i][j].1);
                acc_rev[i][j] = val;
            }
        }
        Self::dfs2(0, n, &g, &mut ch, &acc, &acc_rev, M::e());
        for i in 0..n {
            let l = ch[i].len();
            ch[i].sort_unstable_by_key(|&(eidx, _)| eidx);
            for j in 0..l {
                let val = M::add(&acc[i][j], &ch[i][j].1);
                acc[i][j + 1] = val;
            }
            for j in (0..l).rev() {
                let val = M::add(&acc_rev[i][j + 1], &ch[i][j].1);
                acc_rev[i][j] = val;
            }
        }
        MonoidalReroot {
            acc: acc,
            acc_rev: acc_rev,
        }
    }
    fn dfs1(
        v: usize, par: usize, g: &[Vec<(usize, EIdx)>],
        ch: &mut [Vec<(EIdx, M::E)>],
    ) -> M::V {
        let mut me = M::e();
        for i in 0..g[v].len() {
            let (w, eidx) = g[v][i];
            if w == par { continue; }
            let chval = Self::dfs1(w, v, g, ch);
            let chval = M::put_edge(&chval, eidx);
            ch[v].push((eidx, chval.clone()));
            me = M::add(&me, &chval);
        }
        M::put_vertex(&me, v)
    }
    fn dfs2(
        v: usize, par: usize, g: &[Vec<(usize, EIdx)>],
        ch: &mut [Vec<(EIdx, M::E)>],
        acc: &[Vec<M::E>],
        acc_rev: &[Vec<M::E>],
        passed: M::E,
    ) {
        let mut parenteidx = None;
        for i in 0..g[v].len() {
            let (w, eidx) = g[v][i];
            if w == par {
                parenteidx = Some(eidx);
                continue;
            }
            let j = ch[v].binary_search_by_key(&eidx, |&(eidx, _)| eidx).unwrap();
            let inherited = M::add(&acc[v][j], &acc_rev[v][j + 1]);
            let inherited = if par >= g.len() {
                inherited
            } else {
                M::add(&inherited, &passed)
            };
            let inherited = M::put_vertex(&inherited, v);
            let inherited = M::put_edge(&inherited, eidx);
            Self::dfs2(w, v, g, ch, acc, acc_rev, inherited);
        }
        if let Some(eidx) = parenteidx {
            ch[v].push((eidx, passed.clone()));
        }
    }
    #[inline]
    pub fn query(&self, v: usize) -> M::V {
        M::put_vertex(&self.acc_rev[v][0], v)
    }
}

enum IndepMonoid {}

impl Monoid for IndepMonoid {
    type V = [i64; 2]; // [その頂点を使わない, 使う]
    type E = [i64; 2]; // [一番上を使わない, 使っても良い]
    fn add(a: &Self::E, b: &Self::E) -> Self::E {
        [a[0] + b[0], a[1] + b[1]]
    }
    fn e() -> Self::E {
        [0, 0]
    }
    fn put_edge(&a: &Self::V, _eidx: EIdx) -> Self::E {
        [a[0], std::cmp::max(a[0], a[1])]
    }
    fn put_vertex(a: &Self::E, _vidx: usize) -> Self::V {
        [a[1], a[0] + 1]
    }
}

fn main() {
    // In order to avoid potential stack overflow, spawn a new thread.
    let stack_size = 104_857_600; // 100 MB
    let thd = std::thread::Builder::new().stack_size(stack_size);
    thd.spawn(|| solve()).unwrap().join().unwrap();
}

// Tags: rerooting
fn solve() {
    input! {
        n: usize,
        uv: [(usize1, usize1); n - 1],
    }
    let mut g = vec![vec![]; n];
    for i in 0..n - 1 {
        let (u, v) = uv[i];
        g[u].push((v, i));
        g[v].push((u, i + n));
    }
    let rr = MonoidalReroot::<IndepMonoid>::new(&g);
    let mut ans = rr.query(0)[1];
    for i in 1..n {
        ans = std::cmp::min(ans, rr.query(i)[1]);
    }
    println!("{}", ans);
}
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