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  1. #[allow(unused_imports)]
  2. use std::io::{BufWriter, stdin, stdout, Write};
  3.  
  4. struct Scanner { buffer: Vec<String> }
  5.  
  6. impl Scanner {
  7.     fn next<T: std::str::FromStr>(&mut self) -> T {
  8.         loop {
  9.             if let Some(token) = self.buffer.pop() {
  10.                 return token.parse().ok().expect("parse error");
  11.             }
  12.             let mut input = String::new();
  13.             stdin().read_line(&mut input).expect("read error");
  14.             self.buffer = input.split_whitespace().rev().map(String::from).collect();
  15.         }
  16.     }
  17. }
  18.  
  19. macro_rules! io_init {
  20.     ($scan:ident, $out:ident) => {
  21.         let mut $scan = Scanner { buffer: Vec::new() };
  22.         let $out = &mut BufWriter::new(stdout());
  23.     };
  24. }
  25.  
  26. fn solve(scan: &mut Scanner, out: &mut BufWriter<std::io::Stdout>) {
  27.     let n = scan.next::<usize>();
  28.     let k = scan.next::<usize>();
  29.     let mut a = Vec::with_capacity(n);
  30.     for _ in 0..n {
  31.         a.push(scan.next::<i64>());
  32.     }
  33.     a.sort_unstable();
  34.     let mid1 = k + (n - k + 2) / 2 - 1;
  35.     let mid2 = (n - k + 1) / 2 - 1;
  36.     let res = a[mid1] - a[mid2] + 1;
  37.     writeln!(out, "{}", res).unwrap();
  38. }
  39.  
  40. fn main() {
  41.     io_init!(scan, out);
  42.     let t = scan.next::<i32>();
  43.     for _ in 0..t {
  44.         solve(&mut scan, out);
  45.     }
  46. }
  47.  
Success #stdin #stdout 0.01s 5324KB
comments (?)
stdin
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4
4 0
1 2 3 4
5 2
7 6 6 7 1
3 1
6 7 9
6 2
5 1 9 10 13 2
stdout
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2
2
4
9
https://ideone.com/0go4gw
language:
Rust (rust 1.56)
created:
14 hours ago
visibility:
public

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