#475215 (Rust) No.1044 正直者大学

• 問題: No.1044 正直者大学
• ユーザー: cotton_fn_
• 提出日時: 2020-05-02 05:26:36
• 言語: Rust (1.77.0 + proconio)
• 結果: AC
• 実行時間: 124 ms / 2,000 ms
• コード長: 5,680 bytes
• コンパイル時間: 21,471 ms
• コンパイル使用メモリ: 394,824 KB
• 実行使用メモリ: 6,944 KB
• 最終ジャッジ日時: 2024-06-07 20:53:44
• 合計ジャッジ時間: 23,309 ms
• ジャッジサーバーID （参考情報）: judge1 / judge5

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; 6,816 KB
testcase_02	AC	2 ms; 6,944 KB
testcase_03	AC	2 ms; 6,940 KB
testcase_04	AC	1 ms; 6,940 KB
testcase_05	AC	6 ms; 6,940 KB
testcase_06	AC	124 ms; 6,944 KB
testcase_07	AC	1 ms; 6,940 KB
testcase_08	AC	1 ms; 6,940 KB
testcase_09	AC	1 ms; 6,944 KB
testcase_10	AC	1 ms; 6,944 KB
testcase_11	AC	2 ms; 6,940 KB
testcase_12	AC	9 ms; 6,944 KB
testcase_13	AC	69 ms; 6,940 KB
testcase_14	AC	7 ms; 6,940 KB
testcase_15	AC	15 ms; 6,940 KB
testcase_16	AC	79 ms; 6,940 KB
testcase_17	AC	38 ms; 6,944 KB
testcase_18	AC	52 ms; 6,944 KB
testcase_19	AC	23 ms; 6,944 KB
testcase_20	AC	13 ms; 6,944 KB
testcase_21	AC	20 ms; 6,944 KB
testcase_22	AC	2 ms; 6,940 KB
testcase_23	AC	5 ms; 6,944 KB
testcase_24	AC	4 ms; 6,944 KB
testcase_25	AC	4 ms; 6,944 KB
testcase_26	AC	5 ms; 6,940 KB
testcase_27	AC	1 ms; 6,940 KB
testcase_28	AC	1 ms; 6,940 KB
testcase_29	AC	2 ms; 6,944 KB

ソースコード

#![allow(unused_imports, unused_macros)]

use kyoproio::*;
use std::{
    collections::*,
    io::{self, prelude::*},
    iter,
    mem::{replace, swap},
};

fn main() -> io::Result<()> {
    std::thread::Builder::new()
        .stack_size(64 * 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),+).unwrap(); }; }
    macro_rules! outputln {
        ($($args:expr),+) => { output!($($args),+); outputln!(); };
        () => { output!("\n"); if cfg!(debug_assertions) { out.flush().unwrap(); } }
    }

    const MOD: i64 = 1e9 as i64 + 7;
    let (mut n, mut m, k): (i64, i64, i64) = kin.input();
    if n < m {
        swap(&mut n, &mut m);
    }
    let c = Combination::new((n + m) as usize, MOD);
    let mut ans = 0;
    for i in (1..).take_while(|i| n + m - 2 * i >= k) {
        ans += c.comb(n, i) * c.comb(m - 1, i - 1) % MOD;
    }
    ans %= MOD;
    ans = ans * c.fact(n - 1) % MOD * c.fact(m) % MOD;
    outputln!("{}", ans);
}
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 {
            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 {
    use std::io::prelude::*;
    pub trait Input {
        fn str(&mut self) -> &str;
        fn input<T: InputParse>(&mut self) -> T {
            T::input(self)
        }
        fn iter<T: InputParse>(&mut self) -> Iter<T, Self> {
            Iter(self, 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: ?Sized>(&'a mut I, std::marker::PhantomData<*const T>);
    impl<'a, T: InputParse, I: Input + ?Sized> Iterator for Iter<'a, T, I> {
        type Item = T;
        fn next(&mut self) -> Option<T> {
            Some(self.0.input())
        }
    }
    pub trait InputParse: Sized {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self;
    }
    impl InputParse for Vec<u8> {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self {
            src.str().as_bytes().to_owned()
        }
    }
    macro_rules! from_str_impl {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    src.str().parse::<$T>().expect("parse error")
                }
            })*
        }
    }
    from_str_impl! {
        String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128
    }
    macro_rules! tuple_impl {
        ($H:ident $($T:ident)*) => {
            impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    ($H::input(src), $($T::input(src)),*)
                }
            }
            tuple_impl!($($T)*);
        };
        () => {}
    }
    tuple_impl!(A B C D E F G);
}