結果

問題 No.3345 Reducible Sequence
コンテスト
ユーザー koba-e964
提出日時 2025-11-13 22:28:59
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 292 ms / 2,000 ms
コード長 4,746 bytes
コンパイル時間 12,953 ms
コンパイル使用メモリ 398,388 KB
実行使用メモリ 7,720 KB
最終ジャッジ日時 2025-11-13 22:29:21
合計ジャッジ時間 15,211 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 26
権限があれば一括ダウンロードができます

ソースコード

diff # 

fn getline() -> String {
    let mut ret = String::new();
    std::io::stdin().read_line(&mut ret).unwrap();
    ret
}

// Dinic's algorithm for maximum flow problem.
// This implementation uses O(n) stack space.
// Verified by:
// - yukicoder No.177 (http://yukicoder.me/submissions/148371)
// - ABC239-G (https://atcoder.jp/contests/abc239/submissions/29497217)
#[derive(Clone)]
struct Edge<T> {
    to: usize,
    cap: T,
    rev: usize, // rev is the position of the reverse edge in graph[to]
}

struct Cut {
    is_t: Vec<bool>,
}
#[allow(unused)]
impl Cut {
    pub fn is_cut(&self, s: usize, t: usize) -> bool {
        !self.is_t[s] && self.is_t[t]
    }
    pub fn t(&self) -> Vec<usize> {
        (0..self.is_t.len()).filter(|&v| self.is_t[v]).collect()
    }
    pub fn s(&self) -> Vec<usize> {
        (0..self.is_t.len()).filter(|&v| !self.is_t[v]).collect()
    }
}

struct Dinic<T> {
    graph: Vec<Vec<Edge<T>>>,
    iter: Vec<usize>,
    zero: T,
}

impl<T> Dinic<T>
    where T: Clone,
          T: Copy,
          T: Ord,
          T: std::ops::Add<Output = T>,
          T: std::ops::Sub<Output = T>,
          T: std::ops::AddAssign,
          T: std::ops::SubAssign,
{
    fn bfs(&self, s: usize, t: usize, level: &mut [Option<usize>]) {
        let n = level.len();
        for i in 0..n {
            level[i] = None;
        }
        let mut que = std::collections::VecDeque::new();
        level[s] = Some(0);
        que.push_back(s);
        while let Some(v) = que.pop_front() {
            for e in self.graph[v].iter() {
            if e.cap > self.zero && level[e.to] == None {
                level[e.to] = Some(level[v].unwrap() + 1);
                    if e.to == t { return; }
                que.push_back(e.to);
                }
            }
    }
    }
    // search an augment path with dfs.
    // if f == None, f is treated as infinity.
    fn dfs(&mut self, v: usize, s: usize, f: Option<T>, level: &mut [Option<usize>]) -> T {
        if v == s {
            return f.unwrap();
        }
        let mut res = self.zero;
        while self.iter[v] < self.graph[v].len() {
            let i = self.iter[v];
            let e = self.graph[v][i].clone();
            let cap = self.graph[e.to][e.rev].cap;
            if cap > self.zero && level[e.to].is_some() && level[v] > level[e.to] {
                let newf = std::cmp::min(f.unwrap_or(cap + res) - res, cap);
                let d = self.dfs(e.to, s, Some(newf), level);
                if d > self.zero {
                    self.graph[v][i].cap += d;
                    self.graph[e.to][e.rev].cap -= d;
                    res += d;
                    if Some(res) == f {
                        return res;
                    }
                }
            }
            self.iter[v] += 1;
        }
        res
    }
    pub fn new(n: usize, zero: T) -> Self {
        Dinic {
            graph: vec![Vec::new(); n],
            iter: vec![0; n],
            zero: zero,
        }
    }
    pub fn add_edge(&mut self, from: usize, to: usize, cap: T) {
        if from == to { return; }
        let added_from = Edge {
            to: to, cap: cap,
            rev: self.graph[to].len() };
        let added_to = Edge {
            to: from, cap: self.zero,
            rev: self.graph[from].len() };
        self.graph[from].push(added_from);
        self.graph[to].push(added_to);
    }
    pub fn max_flow(&mut self, s: usize, t: usize) -> (T, Cut) {
        let mut flow = self.zero;
        let n = self.graph.len();
        let mut level = vec![None; n];
        loop {
            self.bfs(s, t, &mut level);
            if level[t] == None {
                let is_t: Vec<bool> = (0..n).map(|v| level[v].is_none())
                    .collect();
                return (flow, Cut { is_t: is_t });
            }
            self.iter.clear();
            self.iter.resize(n, 0);
            let f = self.dfs(t, s, None, &mut level);
            flow += f;
        }
    }
}

fn main() {
    getline();
    let a = getline().trim().split_whitespace()
        .map(|x| x.parse::<usize>().unwrap())
        .collect::<Vec<_>>();
    const W: usize = 5000;
    let mut f = vec![0; W];
    for a in a {
        f[a - 1] += 1;
    }
    let mut din = Dinic::new(2 + W * 2, 0i32);
    for i in 0..W {
        if f[i] != 0 {
            din.add_edge(2 + W + i, 1, f[i]);
        }
    }
    let mut ok = 0;
    for i in 1..W + 1 {
        din.add_edge(0, 2 + i - 1, 1);
        for j in 1..=W / i {
            if f[i * j - 1] != 0 {
                din.add_edge(2 + i - 1, 2 + W + i * j - 1, 1);
            }
        }
        if din.max_flow(0, 1).0 == 0 {
            break;
        }
        ok = i;
    }
    println!("{ok}");
}
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