#1178542 (Rust) No.260 世界のなんとか3

• 問題: No.260 世界のなんとか3
• ユーザー: hayatroid
• 提出日時: 2026-08-23 15:57:03
• 言語: Rust (1.94.0 + proconio + num + itertools)
• 結果: AC
• 実行時間: 830 ms / 2,000 ms
• コード長: 4,111 bytes
• コンパイル時間: 6,303 ms
• コンパイル使用メモリ: 194,856 KB
• 実行使用メモリ: 6,272 KB
• 最終ジャッジ日時: 2026-08-23 15:57:25
• 合計ジャッジ時間: 18,989 ms
• ジャッジサーバーID （参考情報）: judge3_1 / judge1_0

ファイルパターン	結果
sample	AC * 3
other	AC * 27

ソースコード

use std::{cmp::Ordering, collections::HashMap, hash::Hash};

use proconio::{input, marker::Bytes};

fn main() {
    input! {
        a: Bytes,
        b: Bytes,
    }
    let dfa = And(Or(MultipleOf(3), Seen(b'3')), Not(MultipleOf(8)));
    let hi = count(And(dfa.clone(), Le(&b)), b'0'..=b'9', b.len());
    let lo = count(And(dfa.clone(), Lt(&a)), b'0'..=b'9', a.len());
    println!("{}", (hi + MOD - lo) % MOD);
}

const MOD: u64 = 1_000_000_007;

fn count<A>(dfa: A, sigma: impl Iterator<Item = A::Alphabet> + Clone, len: usize) -> u64
where
    A: Dfa,
    A::State: Eq + Hash,
{
    let mut dp = HashMap::new();
    dp.insert(dfa.init(), 1);
    for _ in 0..len {
        let mut ndp = HashMap::new();
        for (q, v) in dp {
            for c in sigma.clone() {
                let e = ndp.entry(dfa.next(&q, &c)).or_insert(0);
                *e = (*e + v) % MOD;
            }
        }
        dp = ndp;
    }
    dp.iter()
        .filter_map(|(q, v)| dfa.accept(q).then_some(v))
        .fold(0, |sum, v| (sum + v) % MOD)
}

trait Dfa {
    type State;
    type Alphabet;
    fn init(&self) -> Self::State;
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State;
    fn accept(&self, q: &Self::State) -> bool;
}

#[derive(Clone)]
struct And<A, B>(A, B);
impl<A: Dfa, B: Dfa<Alphabet = A::Alphabet>> Dfa for And<A, B> {
    type State = (A::State, B::State);
    type Alphabet = A::Alphabet;
    fn init(&self) -> Self::State {
        (self.0.init(), self.1.init())
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        (self.0.next(&q.0, c), self.1.next(&q.1, c))
    }
    fn accept(&self, q: &Self::State) -> bool {
        self.0.accept(&q.0) && self.1.accept(&q.1)
    }
}

#[derive(Clone)]
struct Or<A, B>(A, B);
impl<A: Dfa, B: Dfa<Alphabet = A::Alphabet>> Dfa for Or<A, B> {
    type State = (A::State, B::State);
    type Alphabet = A::Alphabet;
    fn init(&self) -> Self::State {
        (self.0.init(), self.1.init())
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        (self.0.next(&q.0, c), self.1.next(&q.1, c))
    }
    fn accept(&self, q: &Self::State) -> bool {
        self.0.accept(&q.0) || self.1.accept(&q.1)
    }
}

#[derive(Clone)]
struct Not<A>(A);
impl<A: Dfa> Dfa for Not<A> {
    type State = A::State;
    type Alphabet = A::Alphabet;
    fn init(&self) -> Self::State {
        self.0.init()
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        self.0.next(q, c)
    }
    fn accept(&self, q: &Self::State) -> bool {
        !self.0.accept(q)
    }
}

#[derive(Clone)]
struct MultipleOf(u64);
impl Dfa for MultipleOf {
    type State = u64;
    type Alphabet = u8;
    fn init(&self) -> Self::State {
        0
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        (q * 10 + (c - b'0') as u64) % self.0
    }
    fn accept(&self, q: &Self::State) -> bool {
        *q == 0
    }
}

#[derive(Clone)]
struct Seen(u8);
impl Dfa for Seen {
    type State = bool;
    type Alphabet = u8;
    fn init(&self) -> Self::State {
        false
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        *q || *c == self.0
    }
    fn accept(&self, q: &Self::State) -> bool {
        *q
    }
}

#[derive(Clone)]
struct Lt<'a>(&'a [u8]);
impl Dfa for Lt<'_> {
    type State = (Ordering, usize);
    type Alphabet = u8;
    fn init(&self) -> Self::State {
        (Ordering::Equal, 0)
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        (q.0.then(c.cmp(&self.0[q.1])), q.1 + 1)
    }
    fn accept(&self, q: &Self::State) -> bool {
        q.0.is_lt()
    }
}

#[derive(Clone)]
struct Le<'a>(&'a [u8]);
impl Dfa for Le<'_> {
    type State = (Ordering, usize);
    type Alphabet = u8;
    fn init(&self) -> Self::State {
        (Ordering::Equal, 0)
    }
    fn next(&self, q: &Self::State, c: &Self::Alphabet) -> Self::State {
        (q.0.then(c.cmp(&self.0[q.1])), q.1 + 1)
    }
    fn accept(&self, q: &Self::State) -> bool {
        q.0.is_le()
    }
}