#869037 (Rust) No.2299 Antitypoglycemia

• 問題: No.2299 Antitypoglycemia
• ユーザー: so-hey
• 提出日時: 2023-05-12 23:24:15
• 言語: Rust (1.77.0 + proconio)
• 結果: AC
• 実行時間: 5 ms / 2,000 ms
• コード長: 2,905 bytes
• コンパイル時間: 15,001 ms
• コンパイル使用メモリ: 376,984 KB
• 実行使用メモリ: 6,820 KB
• 最終ジャッジ日時: 2024-11-28 20:14:25
• 合計ジャッジ時間: 14,202 ms
• ジャッジサーバーID （参考情報）: judge1 / judge2

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	1 ms; 6,816 KB
testcase_02	AC	1 ms; 5,248 KB
testcase_03	AC	3 ms; 5,248 KB
testcase_04	AC	3 ms; 6,816 KB
testcase_05	AC	3 ms; 6,816 KB
testcase_06	AC	3 ms; 5,248 KB
testcase_07	AC	1 ms; 5,248 KB
testcase_08	AC	3 ms; 5,248 KB
testcase_09	AC	3 ms; 5,248 KB
testcase_10	AC	2 ms; 5,248 KB
testcase_11	AC	2 ms; 5,248 KB
testcase_12	AC	4 ms; 5,248 KB
testcase_13	AC	5 ms; 5,248 KB
testcase_14	AC	1 ms; 5,248 KB
testcase_15	AC	1 ms; 5,248 KB
testcase_16	AC	2 ms; 5,248 KB
testcase_17	AC	1 ms; 5,248 KB
testcase_18	AC	5 ms; 5,248 KB
testcase_19	AC	4 ms; 5,248 KB
testcase_20	AC	4 ms; 5,248 KB
testcase_21	AC	5 ms; 5,248 KB
testcase_22	AC	5 ms; 5,248 KB
testcase_23	AC	1 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	1 ms; 5,248 KB

ソースコード

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(mut x: isize) -> Self {
        if x < 0 { while x < 0 { x += MOD } }
        else { x %= MOD }
        Self { x: x }
    }

    fn inv(self) -> Self {  //逆元
        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);
        }
        Modint::new(u)
    }
}

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 ans: Modint;
    if a == b {
        ans = Modint::new(n as isize - 1) * Modint::new(n as isize - 2) * Modint::new(fac(n as isize - 2));
    } else {
        ans = Modint::new(n as isize - 2) * Modint::new(n as isize - 2) * Modint::new(fac(n as isize - 2))
            + Modint::new(n as isize - 1) * Modint::new(fac(n as isize - 2))
    }
    println!("{}", ans);
}