#700726 (Rust) No.1683 Robot Guidance

• 問題: No.1683 Robot Guidance
• ユーザー: koba-e964
• 提出日時: 2021-09-17 23:20:02
• 言語: Rust (1.77.0)
• 結果: AC
• 実行時間: 49 ms / 2,000 ms
• コード長: 7,076 bytes
• コンパイル時間: 3,722 ms
• コンパイル使用メモリ: 164,240 KB
• 実行使用メモリ: 32,192 KB
• 最終ジャッジ日時: 2023-09-12 09:25:34
• 合計ジャッジ時間: 3,585 ms
• ジャッジサーバーID （参考情報）: judge13 / judge11

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	1 ms; 4,376 KB
testcase_01	AC	1 ms; 4,380 KB
testcase_02	AC	2 ms; 4,376 KB
testcase_03	AC	12 ms; 9,576 KB
testcase_04	AC	4 ms; 4,376 KB
testcase_05	AC	7 ms; 4,380 KB
testcase_06	AC	16 ms; 11,080 KB
testcase_07	AC	14 ms; 10,100 KB
testcase_08	AC	43 ms; 28,032 KB
testcase_09	AC	12 ms; 7,824 KB
testcase_10	AC	26 ms; 17,000 KB
testcase_11	AC	20 ms; 11,860 KB
testcase_12	AC	33 ms; 19,400 KB
testcase_13	AC	20 ms; 16,832 KB
testcase_14	AC	41 ms; 29,272 KB
testcase_15	AC	23 ms; 17,556 KB
testcase_16	AC	1 ms; 4,376 KB
testcase_17	AC	1 ms; 4,376 KB
testcase_18	AC	1 ms; 4,380 KB
testcase_19	AC	1 ms; 4,376 KB
testcase_20	AC	1 ms; 4,376 KB
testcase_21	AC	1 ms; 4,376 KB
testcase_22	AC	19 ms; 16,476 KB
testcase_23	AC	21 ms; 16,544 KB
testcase_24	AC	49 ms; 32,164 KB
testcase_25	AC	22 ms; 16,640 KB
testcase_26	AC	35 ms; 32,192 KB
testcase_27	AC	36 ms; 32,104 KB
testcase_28	AC	21 ms; 16,488 KB
testcase_29	AC	21 ms; 16,548 KB
testcase_30	AC	21 ms; 16,528 KB
testcase_31	AC	19 ms; 14,752 KB
testcase_32	AC	20 ms; 14,768 KB
testcase_33	AC	20 ms; 13,008 KB
testcase_34	AC	20 ms; 13,012 KB
testcase_35	AC	22 ms; 14,872 KB
testcase_36	AC	21 ms; 15,020 KB
testcase_37	AC	15 ms; 11,960 KB
testcase_38	AC	15 ms; 11,944 KB
testcase_39	AC	20 ms; 16,556 KB
testcase_40	AC	1 ms; 4,376 KB

ソースコード

#[allow(unused_imports)]
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),* )) => { ($(read_value!($next, $t)),*) };
    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };
    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };
    ($next:expr, usize1) => (read_value!($next, usize) - 1);
    ($next:expr, [ $t:tt ]) => {{
        let len = read_value!($next, usize);
        read_value!($next, [$t; len])
    }};
    ($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, 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>;

// 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)
}

trait Change { fn chmax(&mut self, x: Self); fn chmin(&mut self, x: Self); }
impl<T: PartialOrd> Change for T {
    fn chmax(&mut self, x: T) { if *self < x { *self = x; } }
    fn chmin(&mut self, x: T) { if *self > x { *self = x; } }
}

fn main() {
    // In order to avoid potential stack overflow, spawn a new thread.
    let stack_size = 104_857_600; // 100 MB
    let thd = std::thread::Builder::new().stack_size(stack_size);
    thd.spawn(|| solve()).unwrap().join().unwrap();
}

fn solve() {
    input!(a: usize, b: usize, x: i32, y: i32);
    if ((x + y) % 2 == 0) != (a % 2 == 0) {
        println!("0");
        return;
    }
    let (fac, invfac) = fact_init(a + b + 1);
    let b = b + 1;
    let mut bs = [b / 4; 4];
    for r in 0..b % 4 {
        bs[r as usize] += 1;
    }
    eprintln!("bs = {:?}", bs);
    let mut tot = MInt::new(0);
    for a0 in 0..a + 1 {
        let mut aa = [0; 4];
        aa[0] = a0 as i32;
        aa[1] = (a as i32 + x + y - 2 * a0 as i32) / 2;
        aa[3] = (a as i32 + x - y - 2 * a0 as i32) / 2;
        aa[2] = a0 as i32 - x;
        if aa.iter().any(|&i| i < 0) {
            continue;
        }
        // eprintln!("aa = {:?}", aa);
        let mut tmp = MInt::new(1);
        for i in 0..4 {
            let a = aa[i] as usize;
            tmp *= if bs[i] > 0 {
                fac[a + bs[i] - 1] * invfac[a] * invfac[bs[i] - 1]
            } else if aa[i] == 0 {
                MInt::new(1)
            } else {
                MInt::new(0)
            };
        }
        tot += tmp;
    }
    println!("{}", tot);
}