結果

問題 No.1191 数え上げを愛したい（数列編）
ユーザー ikdikd
提出日時 2020-08-26 20:40:09
言語 Rust
(1.77.0 + proconio)
結果
AC  
実行時間 22 ms / 2,000 ms
コード長 6,161 bytes
コンパイル時間 16,239 ms
コンパイル使用メモリ 379,128 KB
実行使用メモリ 14,336 KB
最終ジャッジ日時 2024-11-07 13:36:24
合計ジャッジ時間 13,938 ms
ジャッジサーバーID
（参考情報） 		judge1 / 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 10 ms
9,472 KB
testcase_01 AC 16 ms
11,264 KB
testcase_02 AC 13 ms
11,520 KB
testcase_03 AC 11 ms
10,368 KB
testcase_04 AC 18 ms
13,056 KB
testcase_05 AC 8 ms
7,808 KB
testcase_06 AC 21 ms
11,392 KB
testcase_07 AC 16 ms
13,696 KB
testcase_08 AC 16 ms
13,696 KB
testcase_09 AC 16 ms
13,696 KB
testcase_10 AC 16 ms
14,336 KB
testcase_11 AC 16 ms
14,208 KB
testcase_12 AC 16 ms
11,008 KB
testcase_13 AC 17 ms
10,880 KB
testcase_14 AC 22 ms
13,568 KB
testcase_15 AC 5 ms
5,632 KB
testcase_16 AC 5 ms
5,504 KB
testcase_17 AC 3 ms
5,248 KB
testcase_18 AC 4 ms
5,248 KB
testcase_19 AC 6 ms
6,528 KB
testcase_20 AC 5 ms
5,504 KB
testcase_21 AC 4 ms
5,248 KB
testcase_22 AC 11 ms
9,472 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
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 # 

pub struct ProconReader<R: std::io::Read> {
    reader: R,
}

impl<R: std::io::Read> ProconReader<R> {
    pub fn new(reader: R) -> Self {
        Self { reader }
    }
    pub fn get<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf = self
            .reader
            .by_ref()
            .bytes()
            .map(|b| b.unwrap())
            .skip_while(|&byte| byte == b' ' || byte == b'\n' || byte == b'\r')
            .take_while(|&byte| byte != b' ' && byte != b'\n' && byte != b'\r')
            .collect::<Vec<_>>();
        std::str::from_utf8(&buf)
            .unwrap()
            .parse()
            .ok()
            .expect("Parse Error.")
    }
}

#[allow(dead_code)]
mod mint {
    use std::ops::{Add, BitAnd, Div, Mul, Rem, Shr, Sub};

    #[derive(Copy, Clone)]
    pub struct Mint<T> {
        x: T,
        mo: T,
    }
    impl<T> Mint<T>
    where
        T: Copy,
    {
        pub fn new(x: T, mo: T) -> Mint<T> {
            Mint { x, mo }
        }
    }
    impl<T> Mint<T>
    where
        T: Copy,
    {
        pub fn val(&self) -> T {
            self.x
        }
        pub fn mo(&self) -> T {
            self.mo
        }
    }
    impl<T> Add<T> for Mint<T>
    where
        T: Copy,
        T: Add<Output = T>,
        T: Rem<Output = T>,
    {
        type Output = Mint<T>;
        fn add(self, rhs: T) -> Mint<T> {
            Mint::new((self.val() + rhs % self.mo()) % self.mo(), self.mo())
        }
    }
    impl<T> Add<Mint<T>> for Mint<T>
    where
        T: Copy,
        Mint<T>: Add<T, Output = Mint<T>>,
    {
        type Output = Mint<T>;
        fn add(self, rhs: Mint<T>) -> Mint<T> {
            self + rhs.val()
        }
    }
    impl<T> Sub<T> for Mint<T>
    where
        T: Copy,
        T: Add<Output = T>,
        T: Sub<Output = T>,
        T: Rem<Output = T>,
    {
        type Output = Mint<T>;
        fn sub(self, rhs: T) -> Mint<T> {
            Mint::new(
                (self.val() + self.mo() - rhs % self.mo()) % self.mo(),
                self.mo(),
            )
        }
    }
    impl<T> Sub<Mint<T>> for Mint<T>
    where
        T: Copy,
        Mint<T>: Sub<T, Output = Mint<T>>,
    {
        type Output = Mint<T>;
        fn sub(self, rhs: Mint<T>) -> Mint<T> {
            self - rhs.val()
        }
    }
    impl<T> Mul<T> for Mint<T>
    where
        T: Copy,
        T: Mul<Output = T>,
        T: Rem<Output = T>,
    {
        type Output = Mint<T>;
        fn mul(self, rhs: T) -> Mint<T> {
            Mint::new((self.val() * rhs % self.mo()) % self.mo(), self.mo())
        }
    }
    impl<T> Mul<Mint<T>> for Mint<T>
    where
        T: Copy,
        Mint<T>: Mul<T, Output = Mint<T>>,
    {
        type Output = Mint<T>;
        fn mul(self, rhs: Mint<T>) -> Mint<T> {
            self * rhs.val()
        }
    }

    impl<T> Mint<T>
    where
        T: Copy,
        T: Sub<Output = T>,
        T: Div<Output = T>,
        T: PartialOrd,
        T: PartialEq,
        T: BitAnd<Output = T>,
        T: Shr<Output = T>,
        Mint<T>: Mul<Output = Mint<T>>,
    {
        pub fn pow(self, y: T) -> Mint<T> {
            let one = self.mo() / self.mo();
            let zero = self.mo() - self.mo();
            let mut res = Mint::one(self.mo());
            let mut base = self;
            let mut exp = y;
            while exp > zero {
                if (exp & one) == one {
                    res = res * base;
                }
                base = base * base;
                exp = exp >> one;
            }
            res
        }
    }
    impl<T> Div<T> for Mint<T>
    where
        T: Copy,
        T: Sub<Output = T>,
        T: Div<Output = T>,
        T: PartialOrd,
        T: PartialEq,
        T: BitAnd<Output = T>,
        T: Shr<Output = T>,
        Mint<T>: Mul<Output = Mint<T>>,
    {
        type Output = Mint<T>;
        fn div(self, rhs: T) -> Mint<T> {
            let one = self.mo() / self.mo();
            self * Mint::new(rhs, self.mo()).pow(self.mo() - one - one)
        }
    }
    impl<T> Div<Mint<T>> for Mint<T>
    where
        T: Copy,
        Mint<T>: Div<T, Output = Mint<T>>,
    {
        type Output = Mint<T>;
        fn div(self, rhs: Mint<T>) -> Mint<T> {
            self / rhs.val()
        }
    }
    impl<T> Mint<T>
    where
        T: Copy,
        T: Div<Output = T>,
        Mint<T>: Div<Output = Mint<T>>,
    {
        pub fn inv(self) -> Mint<T> {
            Mint::one(self.mo()) / self
        }
    }
    impl<T> std::fmt::Display for Mint<T>
    where
        T: Copy + std::fmt::Display,
    {
        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
            write!(f, "{}", self.val())
        }
    }
    impl<T> Mint<T>
    where
        T: Copy,
        T: Sub<Output = T>,
    {
        pub fn zero(mo: T) -> Mint<T> {
            Mint { x: mo - mo, mo }
        }
    }
    impl<T> Mint<T>
    where
        T: Copy,
        T: Div<Output = T>,
    {
        pub fn one(mo: T) -> Mint<T> {
            Mint { x: mo / mo, mo }
        }
    }
}

fn main() {
    let stdin = std::io::stdin();
    let mut rd = ProconReader::new(stdin.lock());

    let n: usize = rd.get();
    let m: usize = rd.get();
    let a: usize = rd.get();
    let b: usize = rd.get();

    use mint::Mint;
    let mo = 998244353;
    let (fac, fac_inv) = (|n| {
        let mut fac = vec![Mint::zero(mo); n];
        let mut fac_inv = vec![Mint::zero(mo); n];
        fac[0] = Mint::new(1, mo);
        for i in 1..n {
            fac[i] = fac[i - 1] * i;
        }
        fac_inv[n - 1] = fac[n - 1].inv();
        for i in (0..n - 1).rev() {
            fac_inv[i] = fac_inv[i + 1] * (i + 1);
        }
        (fac, fac_inv)
    })(n + m + 1);
    let binom = |a: usize, b: usize| {
        if a < b {
            return Mint::zero(mo);
        }
        fac[a] * fac_inv[b] * fac_inv[a - b]
    };

    let mut ans = Mint::zero(mo);
    for d in (a * (n - 1))..=b {
        if m < d {
            continue;
        }
        ans = ans + binom((d - a * (n - 1)) + (n - 2), n - 2) * (m - d);
    }
    println!("{}", ans * fac[n]);
}
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