#703470 (Rust) No.535 自然数の収納方法

• 問題: No.535 自然数の収納方法
• ユーザー: koba-e964
• 提出日時: 2021-09-29 09:12:02
• 言語: Rust (1.77.0 + proconio)
• 結果: AC
• 実行時間: 30 ms / 2,000 ms
• コード長: 5,170 bytes
• コンパイル時間: 16,010 ms
• コンパイル使用メモリ: 388,272 KB
• 実行使用メモリ: 6,944 KB
• 最終ジャッジ日時: 2024-07-16 06:41:35
• 合計ジャッジ時間: 13,129 ms
• ジャッジサーバーID （参考情報）: judge5 / judge3

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	1 ms; 6,812 KB
testcase_01	AC	1 ms; 6,812 KB
testcase_02	AC	1 ms; 6,812 KB
testcase_03	AC	1 ms; 6,940 KB
testcase_04	AC	1 ms; 6,940 KB
testcase_05	AC	1 ms; 6,940 KB
testcase_06	AC	0 ms; 6,944 KB
testcase_07	AC	6 ms; 6,940 KB
testcase_08	AC	18 ms; 6,944 KB
testcase_09	AC	22 ms; 6,940 KB
testcase_10	AC	26 ms; 6,940 KB
testcase_11	AC	4 ms; 6,940 KB
testcase_12	AC	11 ms; 6,940 KB
testcase_13	AC	1 ms; 6,940 KB
testcase_14	AC	8 ms; 6,944 KB
testcase_15	AC	28 ms; 6,940 KB
testcase_16	AC	17 ms; 6,944 KB
testcase_17	AC	29 ms; 6,944 KB
testcase_18	AC	1 ms; 6,940 KB
testcase_19	AC	30 ms; 6,944 KB
testcase_20	AC	30 ms; 6,944 KB
testcase_21	AC	30 ms; 6,940 KB
testcase_22	AC	30 ms; 6,940 KB

ソースコード

use std::cmp::*;
use std::io::Read;

fn get_word() -> String {
    let stdin = std::io::stdin();
    let mut stdin=stdin.lock();
    let mut u8b: [u8; 1] = [0];
    loop {
        let mut buf: Vec<u8> = Vec::with_capacity(16);
        loop {
            let res = stdin.read(&mut u8b);
            if res.unwrap_or(0) == 0 || u8b[0] <= b' ' {
                break;
            } else {
                buf.push(u8b[0]);
            }
        }
        if buf.len() >= 1 {
            let ret = String::from_utf8(buf).unwrap();
            return ret;
        }
    }
}

#[allow(dead_code)]
fn get<T: std::str::FromStr>() -> T { get_word().parse().ok().unwrap() }

/// 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, 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)]
        struct $struct_name {}
        impl mod_int::Mod for $struct_name { fn m() -> i64 { $modulo } }
    }
}
const MOD: i64 = 1_000_000_007;
define_mod!(P, MOD);
type MInt = mod_int::ModInt<P>;

// O(n^2)
fn calc(n: usize, dp: &[MInt]) -> Vec<MInt> {
    let mut dp = dp.to_vec();
    for i in 0..n - 1 {
        let mut acc = vec![MInt::new(0); n + 1];
        for j in 0..n {
            acc[j + 1] = acc[j] + dp[j];
        }
        let mut ep = vec![MInt::new(0); n];
        let diff = max(1, i);
        for j in 0..n {
            ep[j] = acc[min(n, j + diff)];
        }
        dp = ep;
    }
    dp
}

fn main() {
    let n: usize = get();
    let dp = vec![MInt::new(1); n];
    let dp1 = calc(n, &dp);
    let mut dp = vec![MInt::new(0); n];
    dp[0] = 1.into();
    let dp2 = calc(n, &dp);
    let mut sum = -dp2[n - 1];
    for i in 0..n {
        sum += dp1[i];
    }
    println!("{}", sum);
}