結果

問題 No.1195 数え上げを愛したい（文字列編）
コンテスト
ユーザー cotton_fn_
提出日時 2020-10-14 21:13:00
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 2,089 ms / 3,000 ms
コード長 6,453 bytes
コンパイル時間 15,267 ms
コンパイル使用メモリ 378,732 KB
実行使用メモリ 14,592 KB
最終ジャッジ日時 2024-07-20 19:28:13
合計ジャッジ時間 31,304 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
other AC * 26
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ソースコード

diff # 

#![allow(unused_imports, unused_macros)]

use kyoproio::*;
use std::{
    collections::*,
    io::{self, prelude::*},
    iter,
    mem::{replace, swap},
};

fn main() -> io::Result<()> {
    std::thread::Builder::new()
        .stack_size(64 * 1024 * 1024)
        .spawn(|| {
            run(
                KInput::new(io::stdin().lock()),
                io::BufWriter::new(io::stdout().lock()),
            )
        })?
        .join()
        .unwrap();
    Ok(())
}

fn run<I: Input, O: Write>(mut kin: I, mut out: O) {
    macro_rules! output { ($($args:expr),+) => { write!(&mut out, $($args),+).unwrap(); }; }
    macro_rules! outputln {
        ($($args:expr),+) => { output!($($args),+); outputln!(); };
        () => { output!("\n"); if cfg!(debug_assertions) { out.flush().unwrap(); } }
    }

    let mut c = [0; 26];
    for b in kin.str().bytes() {
        c[(b - b'a') as usize] += 1;
    }

    let mut finv = vec![1; *c.iter().max().unwrap() + 1];
    for i in 2..finv.len() {
        finv[i] = finv[i - 1] * mod_inv(i as i64, P) % P;
    }

    let mut f = vec![1];
    for &c in &c {
        let mut g = finv[..=c].to_owned();
        convolution(&mut f, &mut g);
    }

    let mut ans = 0;
    let mut fact = 1;
    for i in 1..f.len() {
        fact = (fact * i as i64) % P;
        ans = (ans + fact * f[i]) % P;
    }

    outputln!("{}", ans);
}

const P: i64 = 998244353; // 2^23 * 7 * 17 + 1
const PR: i64 = 3;

pub fn dft(a: &mut [i64], inv: bool) {
    // Cooley–Tukey FFT
    debug_assert!(a.len().is_power_of_two());
    let n = a.len();
    for i in 0..n {
        let j = i.reverse_bits().wrapping_shr(n.leading_zeros() + 1);
        if i < j {
            a.swap(i, j);
        }
    }
    let mut w = Vec::with_capacity(n / 2);
    for k in (1..).map(|d| 1 << d).take_while(|&k| k <= n) {
        let r = if inv {
            mod_pow(PR, (P - 1) / k as i64, P)
        } else {
            mod_pow(PR, P - 1 - (P - 1) / k as i64, P)
        };
        w.clear();
        w.extend(std::iter::successors(Some(1), |&w| Some(w * r % P)).take(k / 2));
        for ofs in (0..n).step_by(k) {
            for i in 0..k / 2 {
                let u = ofs + i;
                let v = ofs + i + k / 2;
                let t = w[i] * a[v];
                a[v] = (a[u] - t).rem_euclid(P);
                a[u] = (a[u] + t) % P;
            }
        }
    }
    if inv {
        let d = mod_pow(n as i64, P - 2, P);
        for v in a {
            *v = d * *v % P;
        }
    }
}
pub fn convolution(a: &mut Vec<i64>, b: &mut Vec<i64>) {
    let n = a.len() + b.len() - 1;
    let m = n.next_power_of_two();
    a.resize(m, 0);
    b.resize(m, 0);
    dft(a, false);
    dft(b, false);
    for (x, y) in a.iter_mut().zip(b.iter()) {
        *x = *x * *y % P;
    }
    dft(a, true);
    a.truncate(n);
}
pub fn extgcd(a: i64, b: i64) -> (i64, i64, i64) {
    if b != 0 {
        let (g, y, x) = extgcd(b, a.rem_euclid(b));
        (g, x, y - a / b * x)
    } else {
        (a, 1, 0)
    }
}
pub fn mod_inv(x: i64, m: i64) -> i64 {
    extgcd(x, m).1
}
pub fn mod_pow(mut a: i64, mut b: i64, m: i64) -> i64 {
    let mut y = 1;
    while b > 0 {
        if b & 1 == 1 {
            y = y * a % m;
        }
        a = a * a % m;
        b >>= 1;
    }
    y
}

// -----------------------------------------------------------------------------
pub mod kyoproio {
    use std::io::prelude::*;
    pub trait Input {
        fn str(&mut self) -> &str;
        fn input<T: InputParse>(&mut self) -> T {
            T::input(self)
        }
        fn iter<T: InputParse>(&mut self) -> Iter<T, Self> {
            Iter(self, std::marker::PhantomData)
        }
        fn seq<T: InputParse, B: std::iter::FromIterator<T>>(&mut self, n: usize) -> B {
            self.iter().take(n).collect()
        }
    }
    pub struct KInput<R> {
        src: R,
        buf: String,
        pos: usize,
    }
    impl<R: BufRead> KInput<R> {
        pub fn new(src: R) -> Self {
            Self {
                src,
                buf: String::with_capacity(1 << 12),
                pos: 0,
            }
        }
    }
    impl<R: BufRead> Input for KInput<R> {
        fn str(&mut self) -> &str {
            loop {
                if self.pos >= self.buf.len() {
                    self.pos = 0;
                    self.buf.clear();
                    if self.src.read_line(&mut self.buf).expect("io error") == 0 {
                        return &self.buf;
                    }
                }
                let range = self.pos
                    ..self.buf[self.pos..]
                        .find(|c: char| c.is_ascii_whitespace())
                        .map(|i| i + self.pos)
                        .unwrap_or_else(|| self.buf.len());
                self.pos = range.end + 1;
                if range.end > range.start {
                    return &self.buf[range];
                }
            }
        }
    }
    pub struct Iter<'a, T, I: ?Sized>(&'a mut I, std::marker::PhantomData<*const T>);
    impl<'a, T: InputParse, I: Input + ?Sized> Iterator for Iter<'a, T, I> {
        type Item = T;
        fn next(&mut self) -> Option<T> {
            Some(self.0.input())
        }
    }
    pub trait InputParse: Sized {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self;
    }
    impl InputParse for Vec<u8> {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self {
            src.str().as_bytes().to_owned()
        }
    }
    macro_rules! from_str_impl {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    src.str().parse::<$T>().expect("parse error")
                }
            })*
        }
    }
    from_str_impl! {
        String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128
    }
    macro_rules! tuple_impl {
        ($H:ident $($T:ident)*) => {
            impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    ($H::input(src), $($T::input(src)),*)
                }
            }
            tuple_impl!($($T)*);
        };
        () => {}
    }
    tuple_impl!(A B C D E F G);
    #[macro_export]
    macro_rules! kdbg {
        ($($v:expr),*) => {
            if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) }
        }
    }
}
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