#[allow(unused_macros)] macro_rules! debug { ($($a:expr),* $(,)*) => { #[cfg(debug_assertions)] eprintln!(concat!($("| ", stringify!($a), "={:?} "),*, "|"), $(&$a),*); }; } #[derive(Debug)] struct Input { n: usize, k: i64, a: Vec, } fn main() { let Input { n, k, a } = Input::read(std::io::stdin().lock()); if a.iter().any(|&x| x == k) { println!("Yes"); return; } let mut w = std::collections::HashMap::::new(); let mut bad: i64 = 0; for i in 0..1 << n { let mut sum = 0; let mut unused = 0; for (j, x) in a.iter().enumerate() { if i >> j & 1 == 1 { sum += x; } else { unused += 1; } } *w.entry(sum).or_insert(0) += 1; if sum == k { bad += 1 << unused; } if sum == -k { bad += 1 << unused; } } debug!(w, bad); let mut count = 0; for (s, count1) in &w { if let Some(count2) = w.get(&(s + k)) { count += count1 * count2; } } if k == 0 { debug!(count, bad, 1 << n); count += 1 << n; } count -= bad; debug!(count); println!("{}", if count > 0 { "Yes" } else { "No" }); } impl Input { fn read(mut input: T) -> Input { let (n, k) = { let mut buffer = String::new(); input.read_line(&mut buffer).unwrap(); match &split(&buffer).unwrap()[..] { &[n, k] => (n.parse().unwrap(), k.parse().unwrap()), _ => panic!("input format error: N K"), } }; let a: Vec = { let mut buffer = String::new(); input.read_line(&mut buffer).unwrap(); split(&buffer) .unwrap() .into_iter() .map(|x| x.parse().unwrap()) .collect() }; assert!(matches!(n, 2..=20)); assert!(matches!(k, -1_000_000_000..=1_000_000_000)); assert_eq!(n, a.len()); assert!(a .iter() .all(|x| matches!(x, -1_000_000_000..=1_000_000_000))); Input { n: n, k: k, a: a } } } fn split(s: &str) -> Option> { enum State { Word(usize), Space, End, } let mut state = State::Word(0); let mut ret = Vec::new(); for (i, c) in s.char_indices() { let prev = match state { State::End => return None, State::Word(i) => i, State::Space => { state = State::Word(i); i } }; if c == ' ' || c == '\n' { ret.push(&s[prev..i]); state = if c == ' ' { State::Space } else { State::End }; } } matches!(state, State::End).then(|| ret) } #[test] fn test_split() { assert_eq!(split("word\n"), Some(vec!["word"])); assert_eq!( split("many words separated\n"), Some(vec!["many", "words", "separated"]) ); assert_eq!( split(" extra spaces \n"), Some(vec!["", "extra", "", "spaces", ""]) ); assert_eq!(split("no line feed"), None); assert_eq!(split("extra characters\nafter line feed"), None); }