#![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) -> 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> { 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; fn next(&mut self) -> Option> { 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, } impl Scanner { fn new() -> Self { Scanner { stdin: io::stdin(), buffer: VecDeque::new(), } } fn cin(&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::().ok().unwrap() } fn chars(&mut self) -> Vec { self.cin::().chars().collect() } fn vec(&mut self, n: usize) -> Vec { (0..n).map(|_| self.cin()).collect() } }