結果

問題 No.1311 Reverse Permutation Index
ユーザー cympfh
提出日時 2020-12-09 01:53:56
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 1 ms / 1,500 ms
コード長 4,107 bytes
コンパイル時間 21,154 ms
コンパイル使用メモリ 382,344 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-09-18 23:21:44
合計ジャッジ時間 14,609 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 6
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#![allow(unused_imports, unused_macros, dead_code)]
macro_rules! min {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| min!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = min!($($ys),*);
        if $x < t { $x } else { t }
    }}
}
macro_rules! max {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| max!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = max!($($ys),*);
        if $x > t { $x } else { t }
    }}
}
macro_rules! trace {
    ($x:expr) => {
        #[cfg(debug_assertions)]
        eprintln!(">>> {} = {:?}", stringify!($x), $x)
    };
    ($($xs:expr),*) => { trace!(($($xs),*)) }
}
macro_rules! flush {
    () => {
        std::io::stdout().flush().unwrap();
    };
}
macro_rules! put {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        if let Some(x) = it.next() { print!("{}", x); }
        for x in it { print!(" {}", x); }
        println!("");
    }};
    ($x:expr) => { println!("{}", $x) };
    ($x:expr, $($xs:expr),*) => { print!("{} ", $x); put!($($xs),*) }
}
const M: i64 = 1_000_000_007;
// @num/iter/perm
pub struct Permutation {
    n: usize,
    idx: usize,
}
impl Permutation {
    pub fn new(n: usize) -> Permutation {
        Permutation { n: n, idx: 0 }
    }
    pub fn from(mut perm: Vec<usize>) -> Permutation {
        let n = perm.len();
        let mut idx = 0;
        let mut fact = (1..n).fold(1, |prod, x| prod * x);
        for i in 0..n {
            if i > 0 {
                fact /= n - i;
            }
            idx += perm[i] * fact;
            for j in i + 1..n {
                if perm[j] > perm[i] {
                    perm[j] -= 1;
                }
            }
        }
        Permutation { n, idx }
    }
    pub fn to_vec(&self) -> Option<Vec<usize>> {
        let mut r = vec![0; self.n];
        let mut idx = self.idx;
        for k in 1..self.n {
            r[k] = idx % (k + 1);
            idx /= k + 1;
        }
        if idx > 0 {
            return None;
        }
        r.reverse();
        let mut b = vec![true; self.n];
        b[r[0]] = false;
        for k in 1..self.n {
            let mut count = 0;
            for j in 0..self.n {
                if b[j] {
                    if count == r[k] {
                        r[k] = j;
                        b[j] = false;
                        break;
                    }
                    count += 1;
                }
            }
        }
        Some(r)
    }
}
impl Iterator for Permutation {
    type Item = Vec<usize>;
    fn next(&mut self) -> Option<Vec<usize>> {
        let r = self.to_vec();
        self.idx += 1;
        r
    }
}
fn main() {
    let mut sc = Scanner::new();
    let index: usize = sc.cin();
    let n: usize = sc.cin();
    let perm = Permutation { n, idx: index };
    if let Some(p) = perm.to_vec() {
        let mut xs: Vec<_> = p.iter().enumerate().collect();
        xs.sort_by_key(|&item| item.1);
        let zs: Vec<_> = xs.iter().map(|&item| item.0).collect();
        let perm = Permutation::from(zs.clone());
        put!(perm.idx);
    }
}
use std::collections::VecDeque;
use std::io::{self, Write};
use std::str::FromStr;
struct Scanner {
    stdin: io::Stdin,
    buffer: VecDeque<String>,
}
impl Scanner {
    fn new() -> Self {
        Scanner {
            stdin: io::stdin(),
            buffer: VecDeque::new(),
        }
    }
    fn cin<T: FromStr>(&mut self) -> T {
        while self.buffer.is_empty() {
            let mut line = String::new();
            let _ = self.stdin.read_line(&mut line);
            for w in line.split_whitespace() {
                self.buffer.push_back(String::from(w));
            }
        }
        self.buffer.pop_front().unwrap().parse::<T>().ok().unwrap()
    }
    fn chars(&mut self) -> Vec<char> {
        self.cin::<String>().chars().collect()
    }
    fn vec<T: FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.cin()).collect()
    }
}
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