#916917 (Rust) No.2484 Add to Variables

提出ソース

結果

問題	No.2484 Add to Variables
ユーザー	koba-e964
提出日時	2023-09-30 23:01:32
言語	Rust (1.77.0 + proconio)
結果	AC
実行時間	313 ms / 2,000 ms
コード長	12,141 bytes
コンパイル時間	13,242 ms
コンパイル使用メモリ	381,004 KB
実行使用メモリ	18,764 KB
最終ジャッジ日時	2024-07-23 16:41:52
合計ジャッジ時間	18,675 ms
ジャッジサーバーID （参考情報）	judge1 / judge4

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	1 ms 6,816 KB
testcase_01	AC	1 ms 6,816 KB
testcase_02	AC	1 ms 6,940 KB
testcase_03	AC	1 ms 6,944 KB
testcase_04	AC	1 ms 6,944 KB
testcase_05	AC	1 ms 6,944 KB
testcase_06	AC	1 ms 6,940 KB
testcase_07	AC	1 ms 6,940 KB
testcase_08	AC	1 ms 6,944 KB
testcase_09	AC	1 ms 6,944 KB
testcase_10	AC	1 ms 6,940 KB
testcase_11	AC	2 ms 6,944 KB
testcase_12	AC	3 ms 6,944 KB
testcase_13	AC	2 ms 6,940 KB
testcase_14	AC	3 ms 6,940 KB
testcase_15	AC	1 ms 6,944 KB
testcase_16	AC	4 ms 6,944 KB
testcase_17	AC	72 ms 6,944 KB
testcase_18	AC	150 ms 9,640 KB
testcase_19	AC	313 ms 18,408 KB
testcase_20	AC	16 ms 6,940 KB
testcase_21	AC	311 ms 18,484 KB
testcase_22	AC	16 ms 6,944 KB
testcase_23	AC	72 ms 6,940 KB
testcase_24	AC	311 ms 18,104 KB
testcase_25	AC	152 ms 10,408 KB
testcase_26	AC	72 ms 6,944 KB
testcase_27	AC	147 ms 9,708 KB
testcase_28	AC	151 ms 10,360 KB
testcase_29	AC	152 ms 10,396 KB
testcase_30	AC	34 ms 6,940 KB
testcase_31	AC	310 ms 18,764 KB
testcase_32	AC	311 ms 17,580 KB
testcase_33	AC	310 ms 18,308 KB
testcase_34	AC	72 ms 6,944 KB
testcase_35	AC	151 ms 11,060 KB
testcase_36	AC	72 ms 6,944 KB
testcase_37	AC	153 ms 11,108 KB
testcase_38	AC	152 ms 10,368 KB
testcase_39	AC	310 ms 17,336 KB
testcase_40	AC	8 ms 6,940 KB
testcase_41	AC	72 ms 6,944 KB
testcase_42	AC	34 ms 6,940 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

raw source code

use std::cmp::*;
// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes.by_ref().map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr,) => {};
    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };
    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
}

/// Verified by https://atcoder.jp/contests/abc198/submissions/21774342
mod mod_int {
    use std::ops::*;
    pub trait Mod: Copy { fn m() -> i64; }
    #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
    pub struct ModInt<M> { pub x: i64, phantom: ::std::marker::PhantomData<M> }
    impl<M: Mod> ModInt<M> {
        // x >= 0
        pub fn new(x: i64) -> Self { ModInt::new_internal(x % M::m()) }
        fn new_internal(x: i64) -> Self {
            ModInt { x: x, phantom: ::std::marker::PhantomData }
        }
        pub fn pow(self, mut e: i64) -> Self {
            debug_assert!(e >= 0);
            let mut sum = ModInt::new_internal(1);
            let mut cur = self;
            while e > 0 {
                if e % 2 != 0 { sum *= cur; }
                cur *= cur;
                e /= 2;
            }
            sum
        }
        #[allow(dead_code)]
        pub fn inv(self) -> Self { self.pow(M::m() - 2) }
    }
    impl<M: Mod> Default for ModInt<M> {
        fn default() -> Self { Self::new_internal(0) }
    }
    impl<M: Mod, T: Into<ModInt<M>>> Add<T> for ModInt<M> {
        type Output = Self;
        fn add(self, other: T) -> Self {
            let other = other.into();
            let mut sum = self.x + other.x;
            if sum >= M::m() { sum -= M::m(); }
            ModInt::new_internal(sum)
        }
    }
    impl<M: Mod, T: Into<ModInt<M>>> Sub<T> for ModInt<M> {
        type Output = Self;
        fn sub(self, other: T) -> Self {
            let other = other.into();
            let mut sum = self.x - other.x;
            if sum < 0 { sum += M::m(); }
            ModInt::new_internal(sum)
        }
    }
    impl<M: Mod, T: Into<ModInt<M>>> Mul<T> for ModInt<M> {
        type Output = Self;
        fn mul(self, other: T) -> Self { ModInt::new(self.x * other.into().x % M::m()) }
    }
    impl<M: Mod, T: Into<ModInt<M>>> AddAssign<T> for ModInt<M> {
        fn add_assign(&mut self, other: T) { *self = *self + other; }
    }
    impl<M: Mod, T: Into<ModInt<M>>> SubAssign<T> for ModInt<M> {
        fn sub_assign(&mut self, other: T) { *self = *self - other; }
    }
    impl<M: Mod, T: Into<ModInt<M>>> MulAssign<T> for ModInt<M> {
        fn mul_assign(&mut self, other: T) { *self = *self * other; }
    }
    impl<M: Mod> Neg for ModInt<M> {
        type Output = Self;
        fn neg(self) -> Self { ModInt::new(0) - self }
    }
    impl<M> ::std::fmt::Display for ModInt<M> {
        fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
            self.x.fmt(f)
        }
    }
    impl<M: Mod> ::std::fmt::Debug for ModInt<M> {
        fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
            let (mut a, mut b, _) = red(self.x, M::m());
            if b < 0 {
                a = -a;
                b = -b;
            }
            write!(f, "{}/{}", a, b)
        }
    }
    impl<M: Mod> From<i64> for ModInt<M> {
        fn from(x: i64) -> Self { Self::new(x) }
    }
    // Finds the simplest fraction x/y congruent to r mod p.
    // The return value (x, y, z) satisfies x = y * r + z * p.
    fn red(r: i64, p: i64) -> (i64, i64, i64) {
        if r.abs() <= 10000 {
            return (r, 1, 0);
        }
        let mut nxt_r = p % r;
        let mut q = p / r;
        if 2 * nxt_r >= r {
            nxt_r -= r;
            q += 1;
        }
        if 2 * nxt_r <= -r {
            nxt_r += r;
            q -= 1;
        }
        let (x, z, y) = red(nxt_r, r);
        (x, y - q * z, z)
    }
} // mod mod_int

macro_rules! define_mod {
    ($struct_name: ident, $modulo: expr) => {
        #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
        pub struct $struct_name {}
        impl mod_int::Mod for $struct_name { fn m() -> i64 { $modulo } }
    }
}
const MOD: i64 = 998_244_353;
define_mod!(P, MOD);
type MInt = mod_int::ModInt<P>;

// Depends on MInt.rs
fn fact_init(w: usize) -> (Vec<MInt>, Vec<MInt>) {
    let mut fac = vec![MInt::new(1); w];
    let mut invfac = vec![0.into(); w];
    for i in 1..w {
        fac[i] = fac[i - 1] * i as i64;
    }
    invfac[w - 1] = fac[w - 1].inv();
    for i in (0..w - 1).rev() {
        invfac[i] = invfac[i + 1] * (i as i64 + 1);
    }
    (fac, invfac)
}

// FFT (in-place, verified as NTT only)
// R: Ring + Copy
// Verified by: https://judge.yosupo.jp/submission/53831
// Adopts the technique used in https://judge.yosupo.jp/submission/3153.
mod fft {
    use std::ops::*;
    // n should be a power of 2. zeta is a primitive n-th root of unity.
    // one is unity
    // Note that the result is bit-reversed.
    pub fn fft<R>(f: &mut [R], zeta: R, one: R)
        where R: Copy +
        Add<Output = R> +
        Sub<Output = R> +
        Mul<Output = R> {
        let n = f.len();
        assert!(n.is_power_of_two());
        let mut m = n;
        let mut base = zeta;
        unsafe {
            while m > 2 {
                m >>= 1;
                let mut r = 0;
                while r < n {
                    let mut w = one;
                    for s in r..r + m {
                        let &u = f.get_unchecked(s);
                        let d = *f.get_unchecked(s + m);
                        *f.get_unchecked_mut(s) = u + d;
                        *f.get_unchecked_mut(s + m) = w * (u - d);
                        w = w * base;
                    }
                    r += 2 * m;
                }
                base = base * base;
            }
            if m > 1 {
                // m = 1
                let mut r = 0;
                while r < n {
                    let &u = f.get_unchecked(r);
                    let d = *f.get_unchecked(r + 1);
                    *f.get_unchecked_mut(r) = u + d;
                    *f.get_unchecked_mut(r + 1) = u - d;
                    r += 2;
                }
            }
        }
    }
    pub fn inv_fft<R>(f: &mut [R], zeta_inv: R, one: R)
        where R: Copy +
        Add<Output = R> +
        Sub<Output = R> +
        Mul<Output = R> {
        let n = f.len();
        assert!(n.is_power_of_two());
        let zeta = zeta_inv; // inverse FFT
        let mut zetapow = Vec::with_capacity(20);
        {
            let mut m = 1;
            let mut cur = zeta;
            while m < n {
                zetapow.push(cur);
                cur = cur * cur;
                m *= 2;
            }
        }
        let mut m = 1;
        unsafe {
            if m < n {
                zetapow.pop();
                let mut r = 0;
                while r < n {
                    let &u = f.get_unchecked(r);
                    let d = *f.get_unchecked(r + 1);
                    *f.get_unchecked_mut(r) = u + d;
                    *f.get_unchecked_mut(r + 1) = u - d;
                    r += 2;
                }
                m = 2;
            }
            while m < n {
                let base = zetapow.pop().unwrap();
                let mut r = 0;
                while r < n {
                    let mut w = one;
                    for s in r..r + m {
                        let &u = f.get_unchecked(s);
                        let d = *f.get_unchecked(s + m) * w;
                        *f.get_unchecked_mut(s) = u + d;
                        *f.get_unchecked_mut(s + m) = u - d;
                        w = w * base;
                    }
                    r += 2 * m;
                }
                m *= 2;
            }
        }
    }
}

// Depends on: fft.rs, MInt.rs
// Verified by: ABC269-Ex (https://atcoder.jp/contests/abc269/submissions/39116328)
pub struct FPSOps<M: mod_int::Mod> {
    gen: mod_int::ModInt<M>,
}

impl<M: mod_int::Mod> FPSOps<M> {
    pub fn new(gen: mod_int::ModInt<M>) -> Self {
        FPSOps { gen: gen }
    }
}

impl<M: mod_int::Mod> FPSOps<M> {
    pub fn add(&self, mut a: Vec<mod_int::ModInt<M>>, mut b: Vec<mod_int::ModInt<M>>) -> Vec<mod_int::ModInt<M>> {
        if a.len() < b.len() {
            std::mem::swap(&mut a, &mut b);
        }
        for i in 0..b.len() {
            a[i] += b[i];
        }
        a
    }
    pub fn mul(&self, a: Vec<mod_int::ModInt<M>>, b: Vec<mod_int::ModInt<M>>) -> Vec<mod_int::ModInt<M>> {
        type MInt<M> = mod_int::ModInt<M>;
        let n = a.len() - 1;
        let m = b.len() - 1;
        let mut p = 1;
        while p <= n + m { p *= 2; }
        let mut f = vec![MInt::new(0); p];
        let mut g = vec![MInt::new(0); p];
        for i in 0..n + 1 { f[i] = a[i]; }
        for i in 0..m + 1 { g[i] = b[i]; }
        let fac = MInt::new(p as i64).inv();
        let zeta = self.gen.pow((M::m() - 1) / p as i64);
        fft::fft(&mut f, zeta, 1.into());
        fft::fft(&mut g, zeta, 1.into());
        for i in 0..p { f[i] *= g[i] * fac; }
        fft::inv_fft(&mut f, zeta.inv(), 1.into());
        f.truncate(n + m + 1);
        f
    }
}

// https://yukicoder.me/problems/no/2484 (3.5)
// 操作をそれぞれ S, T_{k+1}, U_{k+1}, V と名付ける。T_k U_{k+1} と SV は同じ結果をもたらすが、それ以外はほとんど自由度がなく 1 通りに定まる。
// c[i] = B[i+1]-B[i] (i >= 1), c[0] = B[1] とすると、各操作は以下のようになる:
// S: なにもしない
// T_{k+1}: 0 番目を +1, k+1 番目を -1 する (0 <= k <= N-2)
// U_{k+1}: k 番目を +1 する (1 <= k <= N-1)
// V: 0 番目を +1 する
// 最終的にすべてゼロの配列を操作によって c と等しくできればよい。
// c[0] + sum_{i>=1} min(c[i], 0) < 0 であれば不可能なので 0 通り。
// そうでないとき、T_? と U_? の必須回数、および追加で必要な V の回数は簡単に求められる。
// V を何個 T_1 U_2, T_2 U_3, T_3 U_4 にするかを全探索すれば、それぞれに対して組み合わせの和を計算すれば良い。
// これは畳み込みでできる。
fn main() {
    input! {
        n: usize, m: usize,
        b: [i64; n],
    }
    let (fac, invfac) = fact_init(m + 1);
    let mut c = vec![0; n];
    c[0] = b[0];
    for i in 1..n {
        c[i] = b[i] - b[i - 1];
    }
    let mut negsum = 0;
    let mut possum = 0;
    for i in 1..n {
        negsum += min(0, c[i]);
        possum += max(0, c[i]);
    }
    if negsum + c[0] < 0 {
        println!("0");
        return;
    }
    // Rules out e.g. m m-1 m
    if possum + c[0] > m as i64 {
        println!("0");
        return;
    }
    let rest = m - (possum + c[0]) as usize;
    let t = (c[0] + negsum) as usize;
    let mut prod = vec![MInt::new(1)];
    let fps = FPSOps::new(MInt::new(3));
    for i in 1..4 {
        let mut a = vec![MInt::new(0); m + 1];
        let x = c[i].abs() as usize;
        for j in 0..m + 1 {
            if 2 * j + x <= m {
                a[2 * j + x] += invfac[j + x] * invfac[j];
            }
        }
        prod = fps.mul(prod, a);
        prod.truncate(m + 1);
    }
    let mut a = vec![MInt::new(0); m + 1];
    for j in 0..min(t, rest) + 1 {
        if t - j + rest - j <= m {
            a[t - j + rest - j] += invfac[t - j] * invfac[rest - j];
        }
    }
    prod = fps.mul(prod, a);
    prod.truncate(m + 1);
    println!("{}", prod[m] * fac[m]);
}