結果

問題 No.1191 数え上げを愛したい（数列編）
ユーザー fukafukatanifukafukatani
提出日時 2020-08-23 23:58:23
言語 Rust
(1.77.0)
結果
AC  
実行時間 117 ms / 2,000 ms
コード長 6,688 bytes
コンパイル時間 781 ms
コンパイル使用メモリ 167,264 KB
実行使用メモリ 10,752 KB
最終ジャッジ日時 2024-04-23 18:42:44
合計ジャッジ時間 2,750 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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 47 ms
5,248 KB
testcase_01 AC 91 ms
8,576 KB
testcase_02 AC 66 ms
5,760 KB
testcase_03 AC 28 ms
5,376 KB
testcase_04 AC 95 ms
8,448 KB
testcase_05 AC 53 ms
5,376 KB
testcase_06 AC 88 ms
10,240 KB
testcase_07 AC 69 ms
5,888 KB
testcase_08 AC 68 ms
5,888 KB
testcase_09 AC 69 ms
5,888 KB
testcase_10 AC 116 ms
8,064 KB
testcase_11 AC 117 ms
8,184 KB
testcase_12 AC 48 ms
5,888 KB
testcase_13 AC 56 ms
7,168 KB
testcase_14 AC 114 ms
10,752 KB
testcase_15 AC 1 ms
5,376 KB
testcase_16 AC 1 ms
5,376 KB
testcase_17 AC 1 ms
5,376 KB
testcase_18 AC 0 ms
5,376 KB
testcase_19 AC 1 ms
5,376 KB
testcase_20 AC 0 ms
5,376 KB
testcase_21 AC 0 ms
5,376 KB
testcase_22 AC 47 ms
5,376 KB
testcase_23 AC 1 ms
5,376 KB
testcase_24 AC 1 ms
5,376 KB
testcase_25 AC 1 ms
5,376 KB
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: associated function `set_modulus` is never used
  --> main.rs:73:8
   |
72 | impl Modulo {
   | ----------- associated function in this implementation
73 |     fn set_modulus(m: i64) {
   |        ^^^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

warning: 1 warning emitted

ソースコード

diff # 

#![allow(unused_imports)]
#![allow(non_snake_case)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let v = read_vec::<usize>();
    let (n, m, a, b) = (v[0], v[1], v[2], v[3]);
    if b < (n - 1) * a {
        println!("0");
        return;
    }
    let mut fact = vec![Modulo(1); n + b + 1];
    for i in 1..fact.len() {
        fact[i] = fact[i - 1] * i as i64;
    }
    let fact_inv = fact.iter().map(|&x| x.inv()).collect::<Vec<_>>();

    let add_max = b - (n - 1) * a;
    let mut coef = vec![Modulo(0); add_max + 1];
    for ai in 0..add_max + 1 {
        coef[ai] = mod_comb(n + ai - 2, ai, &fact, &fact_inv);
    }
    let mut from_left = vec![Modulo(0); add_max + 1];
    from_left[0] = coef[0];
    for ai in 1..add_max + 1 {
        from_left[ai] = from_left[ai - 1] + coef[ai];
    }

    let mut ans = Modulo(0);
    for start in 1..m + 1 {
        if start + (n - 1) * a > m {
            break;
        }
        let cur_max = min(add_max, m - start - (n - 1) * a);
        ans += from_left[cur_max];
        // debug!(start, cur_max, from_left[cur_max]);
    }

    ans *= fact[n];
    println!("{}", ans);
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
struct Modulo(i64);
static mut MODULUS: i64 = 998244353;
impl Modulo {
    fn set_modulus(m: i64) {
        unsafe {
            MODULUS = m;
        }
    }
    fn get_modulus() -> i64 {
        unsafe { MODULUS }
    }
    fn new(x: i64) -> Modulo {
        let m = Modulo::get_modulus();
        if x < 0 {
            Modulo(x % m + m)
        } else if x < m {
            Modulo(x)
        } else {
            Modulo(x % m)
        }
    }
    fn pow(self, p: i64) -> Modulo {
        if p == 0 {
            Modulo(1)
        } else {
            let mut t = self.pow(p / 2);
            t *= t;
            if p & 1 == 1 {
                t *= self;
            }
            t
        }
    }
    fn inv(self) -> Modulo {
        self.pow(Modulo::get_modulus() - 2)
    }
}
impl std::fmt::Display for Modulo {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        self.0.fmt(f)
    }
}
impl std::ops::AddAssign for Modulo {
    fn add_assign(&mut self, other: Modulo) {
        let m = Modulo::get_modulus();
        self.0 += other.0;
        if self.0 >= m {
            self.0 -= m;
        }
    }
}
impl std::ops::MulAssign for Modulo {
    fn mul_assign(&mut self, other: Modulo) {
        let m = Modulo::get_modulus();
        self.0 *= other.0;
        self.0 %= m;
    }
}
impl std::ops::SubAssign for Modulo {
    fn sub_assign(&mut self, other: Modulo) {
        let m = Modulo::get_modulus();
        self.0 += m - other.0;
        if self.0 >= m {
            self.0 -= m;
        }
    }
}
macro_rules! impl_modulo_ops {
    ($imp:ident, $method:ident, $assign_imp:ident, $assign_method:ident) => {
        impl<'a> std::ops::$assign_imp<&'a Modulo> for Modulo {
            fn $assign_method(&mut self, other: &'a Modulo) {
                std::ops::$assign_imp::$assign_method(self, *other);
            }
        }
        impl std::ops::$imp for Modulo {
            type Output = Modulo;
            fn $method(self, other: Modulo) -> Modulo {
                let mut x = self;
                std::ops::$assign_imp::$assign_method(&mut x, other);
                x
            }
        }
        impl<'a> std::ops::$imp<Modulo> for &'a Modulo {
            type Output = Modulo;
            fn $method(self, other: Modulo) -> Modulo {
                std::ops::$imp::$method(*self, other)
            }
        }
        impl<'a> std::ops::$imp<&'a Modulo> for Modulo {
            type Output = Modulo;
            fn $method(self, other: &'a Modulo) -> Modulo {
                std::ops::$imp::$method(self, *other)
            }
        }
        impl<'a, 'b> std::ops::$imp<&'b Modulo> for &'a Modulo {
            type Output = Modulo;
            fn $method(self, other: &'b Modulo) -> Modulo {
                std::ops::$imp::$method(*self, *other)
            }
        }
        impl std::ops::$assign_imp<i64> for Modulo {
            fn $assign_method(&mut self, other: i64) {
                std::ops::$assign_imp::$assign_method(self, Modulo::new(other));
            }
        }
        impl<'a> std::ops::$assign_imp<&'a i64> for Modulo {
            fn $assign_method(&mut self, other: &'a i64) {
                std::ops::$assign_imp::$assign_method(self, *other);
            }
        }
        impl std::ops::$imp<i64> for Modulo {
            type Output = Modulo;
            fn $method(self, other: i64) -> Modulo {
                let mut x = self;
                std::ops::$assign_imp::$assign_method(&mut x, other);
                x
            }
        }
        impl<'a> std::ops::$imp<&'a i64> for Modulo {
            type Output = Modulo;
            fn $method(self, other: &'a i64) -> Modulo {
                std::ops::$imp::$method(self, *other)
            }
        }
        impl<'a> std::ops::$imp<i64> for &'a Modulo {
            type Output = Modulo;
            fn $method(self, other: i64) -> Modulo {
                std::ops::$imp::$method(*self, other)
            }
        }
        impl<'a, 'b> std::ops::$imp<&'b i64> for &'a Modulo {
            type Output = Modulo;
            fn $method(self, other: &'b i64) -> Modulo {
                std::ops::$imp::$method(*self, *other)
            }
        }
    };
}
impl_modulo_ops!(Add, add, AddAssign, add_assign);
impl_modulo_ops!(Mul, mul, MulAssign, mul_assign);
impl_modulo_ops!(Sub, sub, SubAssign, sub_assign);

use std::iter::Sum;
impl Sum for Modulo {
    fn sum<I>(iter: I) -> Self
    where
        I: Iterator<Item = Modulo>,
    {
        iter.fold(Modulo(0), |a, b| a + b)
    }
}

impl<'a> Sum<&'a Modulo> for Modulo {
    fn sum<I>(iter: I) -> Self
    where
        I: Iterator<Item = &'a Self>,
    {
        iter.fold(Modulo(0), |a, b| a + b)
    }
}
fn mod_comb(n: usize, k: usize, fact: &[Modulo], fact_inv: &[Modulo]) -> Modulo {
    assert!(n >= k);
    fact[n] * fact_inv[n - k] * fact_inv[k]
}
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