結果

問題 No.1301 Strange Graph Shortest Path
コンテスト
ユーザー phspls
提出日時 2022-11-17 11:19:44
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 158 ms / 3,000 ms
コード長 3,891 bytes
コンパイル時間 12,384 ms
コンパイル使用メモリ 390,400 KB
実行使用メモリ 40,448 KB
最終ジャッジ日時 2024-09-19 00:26:18
合計ジャッジ時間 19,913 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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 * 2
other AC * 33
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: variable `N` should have a snake case name
  --> src/main.rs:50:13
   |
50 |         let N = self.paths.len();
   |             ^ help: convert the identifier to snake case: `n`
   |
   = note: `#[warn(non_snake_case)]` on by default

ソースコード

diff # 

use std::{cmp::Reverse, collections::BinaryHeap};

const INF: isize = 1isize << 60;

#[derive(Debug, Clone, Copy)]
struct MinCostFlowEdge {
    dest: usize,
    capacity: isize,
    cost: isize,
    rev: usize,
}

impl MinCostFlowEdge {
    fn new(dest: usize, capacity: isize, cost: isize, rev: usize) -> MinCostFlowEdge {
        MinCostFlowEdge { dest, capacity, cost, rev }
    }
}

struct MinCostFlow {
    paths: Vec<Vec<MinCostFlowEdge>>,
    potential: Vec<isize>,
    min_cost: Vec<isize>,
    prevv: Vec<usize>,
    preve: Vec<usize>,
}

/*
  最小費用龍。
  fの分だけ流すのにかかる最小のコスト
*/
impl MinCostFlow {
    fn new(n: usize) -> MinCostFlow {
        MinCostFlow {
            paths: vec![vec![]; n],
            potential: vec![0isize; n],
            min_cost: vec![0isize; n],
            prevv: vec![0usize; n],
            preve: vec![0usize; n],
        }
    }

    fn pusha2b(&mut self, a: usize, b: usize, capacity: isize, cost: isize) {
        let connecta = self.paths[a].len();
        let connectb = self.paths[b].len();
        self.paths[a].push(MinCostFlowEdge::new(b, capacity, cost, connectb));
        self.paths[b].push(MinCostFlowEdge::new(a, 0, -cost, connecta));
    }

    fn mincost_flow(&mut self, s: usize, t: usize, _f: isize) -> isize {
        let N = self.paths.len();
        let mut ret = 0isize;
        let mut que = BinaryHeap::new();
        self.potential = vec![0isize; N];
        let mut f = _f;
        while f > 0 {
            self.min_cost = vec![INF; N];
            que.push(Reverse((0, s)));
            self.min_cost[s] = 0;
            while let Some(Reverse((p, v))) = que.pop() {
                if self.min_cost[v] < p { continue; }
                for i in 0..self.paths[v].len() {
                    let edge = self.paths[v][i];
                    let ncost = self.min_cost[v] + edge.cost + self.potential[v] - self.potential[edge.dest];
                    if edge.capacity > 0 && self.min_cost[edge.dest] > ncost {
                        self.min_cost[edge.dest] = ncost;
                        self.prevv[edge.dest] = v;
                        self.preve[edge.dest] = i;
                        que.push(Reverse((self.min_cost[edge.dest], edge.dest)));
                    }
                }
            }
            if self.min_cost[t] == INF {
                return -1;
            }
            for i in 0..N { self.potential[i] += self.min_cost[i]; }

            let mut d = f;
            let mut temp = t;
            while temp != s {
                d = d.min(self.paths[self.prevv[temp]][self.preve[temp]].capacity);
                temp = self.prevv[temp];
            }
            f -= d;
            ret += d * self.potential[t];
            temp = t;
            while temp != s {
                let edge = self.paths[self.prevv[temp]][self.preve[temp]];
                self.paths[self.prevv[temp]][self.preve[temp]].capacity -= d;
                self.paths[temp][edge.rev].capacity += d;
                temp = self.prevv[temp];
            }
        }
        ret
    }
}

fn main() {
    let mut nm = String::new();
    std::io::stdin().read_line(&mut nm).ok();
    let nm: Vec<usize> = nm.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nm[0];
    let m = nm[1];
    let mut flow = MinCostFlow::new(n);
    for _ in 0..m {
        let mut uvcd = String::new();
        std::io::stdin().read_line(&mut uvcd).ok();
        let uvcd: Vec<usize> = uvcd.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let u = uvcd[0]-1;
        let v = uvcd[1]-1;
        let c = uvcd[2] as isize;
        let d = uvcd[3] as isize;
        flow.pusha2b(u, v, 1, c);
        flow.pusha2b(v, u, 1, c);
        flow.pusha2b(u, v, 1, d);
        flow.pusha2b(v, u, 1, d);
    }
    println!("{}", flow.mincost_flow(0, n-1, 2));
}
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