use proconio::input; fn main() { input! { n: usize, } match solve(n) { Some(aa) => println!( "Yes\n{}", aa.iter() .map(|a| a.to_string()) .collect::>() .join(" ") ), None => println!("No"), } } fn solve(n: usize) -> Option> { if n == 2 { return None; } let mut aa = (1..=n).collect::>(); if n % 2 == 0 { aa.swap(n - 2, n - 1); } Some(aa) } #[cfg(test)] mod tests { use itertools::Itertools; fn round_robin(n: usize) -> Option> { (1..=n).permutations(n).find(|perm| { perm.iter() .circular_tuple_windows() .map(|(a1, a2)| a1 + a2) .all_unique() }) } #[test] fn test() { for n in 2..=8 { match round_robin(n) { Some(aa) => println!("{n}: {}", aa.iter().join(" ")), None => println!("{n}: No Solution"), } } } }