use std::cmp::*; use std::io::Read; fn get_word() -> String { let stdin = std::io::stdin(); let mut stdin=stdin.lock(); let mut u8b: [u8; 1] = [0]; loop { let mut buf: Vec = Vec::with_capacity(16); loop { let res = stdin.read(&mut u8b); if res.unwrap_or(0) == 0 || u8b[0] <= b' ' { break; } else { buf.push(u8b[0]); } } if buf.len() >= 1 { let ret = String::from_utf8(buf).unwrap(); return ret; } } } #[allow(dead_code)] fn get() -> T { get_word().parse().ok().unwrap() } // https://yukicoder.me/problems/no/873 (3) // ナップサックで最小の長さを求める。ただし使用する優先度は 1 > 3 > 5 > ... > 6 > 4 > 2 // である。-> そうでもない。偶数を使った後は優先順位が逆転する。 // Tags: knapsack fn main() { let n: usize = get(); const INF: usize = 1 << 20; let mut dp = vec![(INF, 0); n + 1]; let mut dpe = vec![(INF, 0); n + 1]; dp[0] = (0, 0); for i in 1..275 { let v = 2 * i; for j in v * v..n + 1 { let (p, _) = dp[j - v * v]; dp[j] = min(dp[j], (p + v, v)); } } for i in (0..275).rev() { let v = 2 * i + 1; for j in v * v..n + 1 { let (p, _) = dp[j - v * v]; dp[j] = min(dp[j], (p + v, v)); } } dpe[0] = (0, 0); for i in (1..275).rev() { let v = 2 * i; for j in v * v..n + 1 { let (p, _) = dpe[j - v * v]; dpe[j] = min(dpe[j], (p + v, v)); } } let mut path = vec![]; let mut cur = n; let mut even = false; while cur > 0 { let t = if even { dpe[cur].1 } else { dp[cur].1 }; if even { assert_eq!(dpe[cur].0, dp[cur].0); } path.push(t); cur -= t * t; if t % 2 == 0 { even = !even; } } eprintln!("path = {:?}", path); let mut bias = 0; for v in path { for i in 0..v { print!("{}", (i + bias) % 2); } bias += v + 1; } println!(); }