#460013 (Rust) No.813 ユキちゃんの冒険

• 問題: No.813 ユキちゃんの冒険
• ユーザー: cotton_fn_
• 提出日時: 2020-04-07 17:03:56
• 言語: Rust (1.77.0 + proconio)
• 結果: AC
• 実行時間: 1 ms / 2,000 ms
• コード長: 5,235 bytes
• コンパイル時間: 11,825 ms
• コンパイル使用メモリ: 379,956 KB
• 実行使用メモリ: 5,376 KB
• 最終ジャッジ日時: 2024-09-21 08:34:23
• 合計ジャッジ時間: 12,893 ms
• ジャッジサーバーID （参考情報）: judge3 / judge1

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	1 ms; 5,248 KB
testcase_01	AC	1 ms; 5,376 KB
testcase_02	AC	1 ms; 5,376 KB
testcase_03	AC	1 ms; 5,376 KB
testcase_04	AC	1 ms; 5,376 KB
testcase_05	AC	1 ms; 5,376 KB
testcase_06	AC	1 ms; 5,376 KB
testcase_07	AC	1 ms; 5,376 KB
testcase_08	AC	1 ms; 5,376 KB
testcase_09	AC	1 ms; 5,376 KB
testcase_10	AC	1 ms; 5,376 KB
testcase_11	AC	1 ms; 5,376 KB
testcase_12	AC	1 ms; 5,376 KB
testcase_13	AC	1 ms; 5,376 KB
testcase_14	AC	1 ms; 5,376 KB
testcase_15	AC	1 ms; 5,376 KB
testcase_16	AC	1 ms; 5,376 KB
testcase_17	AC	1 ms; 5,376 KB
testcase_18	AC	1 ms; 5,376 KB
testcase_19	AC	1 ms; 5,376 KB
testcase_20	AC	1 ms; 5,376 KB
testcase_21	AC	1 ms; 5,376 KB
testcase_22	AC	1 ms; 5,376 KB
testcase_23	AC	1 ms; 5,376 KB
testcase_24	AC	1 ms; 5,376 KB
testcase_25	AC	1 ms; 5,376 KB

ソースコード

#![allow(unused)]

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

fn main() -> io::Result<()> {
    std::thread::Builder::new()
        .stack_size(10 * 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(); } }
    }

    let (n, p, q): (usize, f64, f64) = kin.input();
    let mut pc = p;
    let mut qc = q;
    for _ in 1..n {
        let d = 1. - pc * p;
        pc = pc + qc * qc * p / d;
        qc = qc * q / d;
    }
    outputln!("{}", pc);
}

use std::cell::UnsafeCell;
struct Lazy<T, F>(UnsafeCell<Inner<T, F>>);
enum Inner<T, F> {
    Thunk(F),
    Value(T),
    Empty,
}
use Inner::*;
impl<T, F: FnOnce() -> T> Lazy<T, F> {
    fn thunk(f: F) -> Self {
        Self(UnsafeCell::new(Thunk(f)))
    }
    fn value(v: T) -> Self {
        Self(UnsafeCell::new(Value(v)))
    }
    fn get(&self) -> &T {
        unsafe {
            if let Thunk(_) = &*self.0.get() {
                if let Thunk(f) = self.0.get().replace(Empty) {
                    self.0.get().replace(Value(f()));
                }
            }
            match &*self.0.get() {
                Value(v) => v,
                _ => unreachable!(),
            }
        }
    }
    fn into_inner(self) -> T {
        self.get();
        match self.0.into_inner() {
            Value(v) => v,
            _ => unreachable!()
        }
    }
}

// -----------------------------------------------------------------------------
pub mod kyoproio {
    #![warn(unused)]
    use std::io::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::Err> {
            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<*const 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())
        }
    }
    pub trait InputParse: Sized {
        type Err: std::fmt::Debug;
        fn input<I: Input>(input: &mut I) -> Result<Self, Self::Err>;
    }
    macro_rules! from_str_impls {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                type Err = <$T as std::str::FromStr>::Err;
                fn input<I: Input>(input: &mut I) -> Result<Self, Self::Err> {
                    input.str().parse::<$T>()
                }
            })*
        };
    }
    from_str_impls! {
        String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128
    }
    macro_rules! tuple_impls {
        ($H:ident $($T:ident)*) => {
            impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) {
                type Err = ();
                fn input<I: Input>(input: &mut I) -> Result<Self, Self::Err> {
                    // ?
                    Ok(($H::input(input).unwrap(), $($T::input(input).unwrap()),*))
                }
            }
            tuple_impls!($($T)*);
        };
        () => {};
    }
    tuple_impls!(A B C D E F G);
}