結果

問題 No.2299 Antitypoglycemia
ユーザー so-hey
提出日時 2023-05-12 23:06:29
言語 Rust
(1.83.0 + proconio)
結果
WA  
実行時間 -
コード長 3,172 bytes
コンパイル時間 10,873 ms
コンパイル使用メモリ 396,904 KB
実行使用メモリ 6,820 KB
最終ジャッジ日時 2024-11-28 19:46:42
合計ジャッジ時間 12,166 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge3
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 * 22 WA * 3
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: value assigned to `ans` is never read
   --> src/main.rs:114:13
    |
114 |     let mut ans = Modint::new(0);
    |             ^^^
    |
    = help: maybe it is overwritten before being read?
    = note: `#[warn(unused_assignments)]` on by default

warning: method `pow` is never used
  --> src/main.rs:30:8
   |
9  | impl Modint {
   | ----------- method in this implementation
...
30 |     fn pow(self, n: isize) -> Self {
   |        ^^^
   |
   = note: `#[warn(dead_code)]` on by default

ソースコード

diff # 

use std::{ops::*, fmt::*, mem::*};

const MOD: isize = 998244353;
//const MOD: isize = 1000000007;
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
struct Modint {
    x: isize
}
impl Modint {
    fn new(x: isize) -> Self {
        if x < 0 { Self {x: x + MOD} }
        else { Self {x: x % MOD} }
    }

    fn inv(self) -> Self {
        let mut a = self.x;
        let mut b = MOD;
        let mut u: isize = 1;
        let mut v: isize = 0;
        while b != 0 {
            let t = a / b;
            a -= t * b;
            u -= t * v;
            swap(&mut a, &mut b);
            swap(&mut u, &mut v);
        }
        Self { x: (u % MOD + MOD) % MOD }
    }

    fn pow(self, n: isize) -> Self {
        if n == 1 { Self { x: self.x % MOD } }
        else if n % 2 == 1 { Self {x: (self.x * self.pow(n - 1).x) % MOD } }
        else { Self { x: self.pow(n / 2).x.pow(2) % MOD } }
    }
}

impl Add for Modint {
    type Output = Modint;
    fn add(self, rhs: Modint) -> Self {
        Self::new(self.x + rhs.x)
    }
}
impl AddAssign for Modint {
    fn add_assign(&mut self, rhs: Self) {
        self.x = (*self + rhs).x;
    }
}impl Sub for Modint {
    type Output = Modint;
    fn sub(self, rhs: Modint) -> Self {
        Self::new(self.x - rhs.x + MOD)
    }
}
impl SubAssign for Modint {
    fn sub_assign(&mut self, rhs: Self) {
        self.x = (*self - rhs).x;
    }
}
impl Mul for Modint {
    type Output = Modint;
    fn mul(self, rhs: Modint) -> Self {
        Self::new(self.x * rhs.x)
    }
}
impl MulAssign for Modint {
    fn mul_assign(&mut self, rhs: Self) {
        self.x = (*self * rhs).x;
    }
}
impl Div for Modint {
    type Output = Modint;
    fn div(self, rhs: Self) -> Self {
        self * rhs.inv()
    }
}
impl DivAssign for Modint {
    fn div_assign(&mut self, rhs: Self) {
        self.x = (*self / rhs).x;
    }
}
impl Display for Modint {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
        write!(f, "{}", self.x)
    }
}

fn fac(n: isize) -> isize {
    if n <= 1 {
        return 1
    } else {
        return (n * fac(n - 1)) % MOD
    }
}

fn main() {
    let (n, a, b): (usize, usize, usize) = {  // 定数個の整数を受け取り, 定数個の変数に束縛する
        let mut line: String = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse().unwrap(),
            iter.next().unwrap().parse().unwrap(),
            iter.next().unwrap().parse().unwrap()
        )
    };
    if n == 2 {
        if a == b {
            println!("{}", 0);
            return
        } else {
            println!("{}", 1);
            return
        }
    }
    let mut ans = Modint::new(0);
    if a == b {
        ans = Modint::new(n as isize - 1) * Modint::new(n as isize - 2) * Modint::new(fac(n as isize - 3));
    } else {
        ans = Modint::new(n as isize - 2) * Modint::new(n as isize - 3) * Modint::new(fac(n as isize - 2)) + Modint::new(2) * Modint::new(n as isize - 2) * Modint::new(fac(n as isize - 2)) + Modint::new(fac(n as isize - 2));
    }
    println!("{}", ans);
}
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