#450247 (Rust) No.895 MESE

• 問題: No.895 MESE
• ユーザー: cotton_fn_
• 提出日時: 2020-03-28 03:23:59
• 言語: Rust (1.83.0 + proconio)
• 結果: AC
• 実行時間: 130 ms / 2,000 ms
• コード長: 6,709 bytes
• コンパイル時間: 13,787 ms
• コンパイル使用メモリ: 388,216 KB
• 実行使用メモリ: 6,820 KB
• 最終ジャッジ日時: 2025-01-02 10:36:00
• 合計ジャッジ時間: 15,065 ms
• ジャッジサーバーID （参考情報）: judge1 / judge5

ファイルパターン	結果
sample	AC * 3
other	AC * 26

ソースコード

#![allow(unused)]
use kyoproio::*;
use std::{
    collections::*,
    iter,
    mem::{replace, swap},
};

fn main() -> io::Result<()> {
    std::thread::Builder::new()
        .stack_size(50 * 1024 * 1024)
        .spawn(solve)?
        .join()
        .unwrap();
    Ok(())
}

fn solve() {
    let stdin = io::stdin();
    let mut kin = KInput::new(stdin.lock());
    let stdout = io::stdout();
    let mut out = io::BufWriter::new(stdout.lock());
    macro_rules! output {
        ($($args:expr),+) => { write!(&mut out, $($args),+) };
    }
    macro_rules! outputln {
        ($($args:expr),+) => { output!($($args),+); outputln!() };
        () => { output!("\n"); if cfg!(debug_assertions) { out.flush(); } }
    }

    const MOD: i64 = 1e9 as i64 + 7;
    let (a, b, c): (i64, i64, i64) = kin.input();
    let n = a + b + c;
    let cb = Combination::new(n as usize, MOD);
    let ones: Vec<_> = iter::successors(Some(0), |x| Some(2 * x % MOD + 1))
        .take(n as usize)
        .collect();
    let mut s = 0;
    for i in 1..=a {
        let ra = a - i;
        let rb = b - 1;
        let rc = c - 1;
        s += cb.comb(ra + rb, ra) * cb.comb(ra + rb + rc, rc) % MOD * ones[(n - i - 1) as usize] % MOD;
    }
    s %= MOD;
    outputln!("{}", s);
}
pub fn mod_pow(mut a: i64, mut b: i64, m: i64) -> i64 {
    let mut y = 1;
    while b > 0 {
        if b & 1 == 1 {
            y = y * a % m;
        }
        a = a * a % m;
        b >>= 1;
    }
    y
}
pub fn mod_inv(x: i64, m: i64) -> i64 {
    mod_pow(x, m - 2, m)
}
pub struct Combination {
    m: i64,
    fact: Vec<i64>,
}
impl Combination {
    pub fn new(size: usize, m: i64) -> Self {
        let mut comb = Self {
            m,
            fact: Vec::new(),
        };
        comb.resize(size);
        comb
    }
    pub fn resize(&mut self, size: usize) {
        let old_len = self.fact.len();
        self.fact.resize(size + 1, 0);
        for i in old_len..size + 1 {
            self.fact[i] = if i == 0 {
                1
            } else {
                i as i64 * self.fact[i - 1] % self.m
            };
        }
    }
    pub fn fact(&self, x: i64) -> i64 {
        self.fact[x as usize]
    }
    pub fn perm(&self, a: i64, b: i64) -> i64 {
        if a >= b {
            self.fact(a) * self.inv(self.fact(a - b)) % self.m
        } else {
            0
        }
    }
    pub fn comb(&self, a: i64, b: i64) -> i64 {
        if a >= b {
            self.fact(a) * self.inv(self.fact(b) * self.fact(a - b) % self.m) % self.m
        } else {
            0
        }
    }
    pub fn pow(&self, a: i64, b: i64) -> i64 {
        mod_pow(a, b, self.m)
    }
    pub fn inv(&self, x: i64) -> i64 {
        self.pow(x, self.m - 2)
    }
}

// -----------------------------------------------------------------------------
pub mod kyoproio {
    #![warn(unused)]

    pub use std::io::{self, prelude::*};

    pub trait Input: Sized {
        fn str(&mut self) -> &str;
        fn bytes(&mut self) -> &[u8] {
            self.str().as_ref()
        }
        fn input<T: InputParse>(&mut self) -> T {
            self.input_fallible().expect("input error")
        }
        fn input_fallible<T: InputParse>(&mut self) -> Result<T> {
            T::input(self)
        }
        fn iter<T: InputParse>(&mut self) -> Iter<T, Self> {
            Iter {
                input: self,
                _t: std::marker::PhantomData,
            }
        }
        fn seq<T: InputParse, B: std::iter::FromIterator<T>>(&mut self, n: usize) -> B {
            self.iter().take(n).collect()
        }
    }
    pub struct KInput<R> {
        src: R,
        buf: String,
        pos: usize,
    }
    impl<R: BufRead> KInput<R> {
        pub fn new(src: R) -> Self {
            Self {
                src,
                buf: String::with_capacity(1024),
                pos: 0,
            }
        }
    }
    impl<R: BufRead> Input for KInput<R> {
        fn str(&mut self) -> &str {
            loop {
                if self.pos >= self.buf.len() {
                    self.pos = 0;
                    self.buf.clear();
                    if self.src.read_line(&mut self.buf).expect("io error") == 0 {
                        return &self.buf;
                    }
                }
                let range = self.pos
                    ..self.buf[self.pos..]
                        .find(|c: char| c.is_ascii_whitespace())
                        .map(|i| i + self.pos)
                        .unwrap_or_else(|| self.buf.len());
                self.pos = range.end + 1;
                if range.end > range.start {
                    return &self.buf[range];
                }
            }
        }
    }
    pub struct Iter<'a, T, I> {
        input: &'a mut I,
        _t: std::marker::PhantomData<T>,
    }
    impl<'a, T: InputParse, I: Input> Iterator for Iter<'a, T, I> {
        type Item = T;
        fn next(&mut self) -> Option<Self::Item> {
            Some(self.input.input())
        }
    }
    type Result<T> = std::result::Result<T, Box<dyn std::error::Error + 'static>>;
    pub trait InputParse: Sized {
        fn input<I: Input>(input: &mut I) -> Result<Self>;
    }
    macro_rules! input_from_str_impls {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                fn input<I: Input>(input: &mut I) -> Result<Self> {
                    input.str().parse::<$T>().map_err(|e| e.into())
                }
            })*
        };
    }
    input_from_str_impls! {
        String char bool f32 f64
        isize i8 i16 i32 i64 i128
        usize u8 u16 u32 u64 u128
    }
    macro_rules! input_tuple_impls {
        ($H:ident, $($T:ident),+) => {
            impl<$H: InputParse, $($T: InputParse),+> InputParse for ($H, $($T),+) {
                fn input<I: Input>(input: &mut I) -> Result<Self> {
                    Ok(($H::input(input)?, $($T::input(input)?),+))
                }
            }
            input_tuple_impls!($($T),+);
        };
        ($H:ident) => {};
    }
    input_tuple_impls!(A, B, C, D, E, F, G);
    /*
    impl<T: InputParse, const N: usize> InputParse for [T; N] {
        fn input<I: Input>(input: &mut I) -> Result<Self> {
            let mut a = std::mem::MaybeUninit::<[T; N]>::uninit();
            for i in 0..N {
                match T::input(input) {
                    Ok(v) => unsafe { std::ptr::write(&mut (*a.as_mut_ptr())[i], v) },
                    Err(e) => unsafe {
                        std::ptr::drop_in_place(&mut (*a.as_mut_ptr())[..i]);
                        return Err(e);
                    },
                }
            }
            Ok(unsafe { a.assume_init() })
        }
    }
    */
}