use std::io; use std::io::{BufRead, Write}; use std::ops::{Rem, Div, Mul}; macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; (stdin = $s:expr, $($r:tt)*) => { let s = { let mut s = String::new(); $s.read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } #[allow(unused_macros)] macro_rules! assert_judge { ($method:ident, $input:expr, $expected:expr) => { { let input = $input.as_bytes(); let mut output = Vec::new(); $method(&input[..], &mut output); let output = String::from_utf8(output).expect("Not UTF-8"); assert_eq!($expected, output); } }; } #[allow(unused_macros)] macro_rules! assert_judge_with_output { ($method:ident, $input:expr) => { { let input = $input.as_bytes(); let mut output = Vec::new(); $method(&input[..], &mut output); String::from_utf8(output).expect("Not UTF-8") } }; } #[allow(unused_macros)] macro_rules! assert_eq_with_error { ($left:expr, $right:expr, $precision:expr) => ({ match (&$left, &$right, &$precision) { (left_val, right_val, precision_val) => { if !(*left_val - *precision_val < *right_val && *right_val < *left_val + *precision_val) { // The reborrows below are intentional. Without them, the stack slot for the // borrow is initialized even before the values are compared, leading to a // noticeable slow down. panic!(r#"assertion failed: `(left == right) +- precision` left: `{:?}`, right: `{:?}`, precision: `{:?}`"#, &*left_val, &*right_val, &*precision_val) } } } }); } trait GenericInteger: Copy + PartialEq + Rem + Div + Mul { fn zero() -> Self; } macro_rules! dec_gi { () => {}; ($t:ty $(, $r:ty)*) => { impl GenericInteger for $t { fn zero() -> Self { 0 } } dec_gi![ $( $r ),* ]; }; } dec_gi![u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize]; #[allow(dead_code)] fn gcd(a: T, b: T) -> T where T: GenericInteger { if b == T::zero() { a } else { gcd(b, a % b) } } #[allow(dead_code)] fn lcm(a: T, b: T) -> T where T: GenericInteger { a / gcd(a, b) * b } #[allow(unused_macros)] macro_rules! swap { ($v1:expr, $v2:expr) => { let buf = $v1; $v1 = $v2; $v2 = buf; }; } fn main() { let stdio = io::stdin(); let input = stdio.lock(); let output = io::stdout(); process(input, output); } fn process(mut reader: R, mut writer: W) -> () where R: BufRead, W: Write { input! { stdin = reader, n: usize, k: usize, d: [usize; n] } let mut d: Vec = d; // symmetric group // extra 2n steps is okay let mut counter = 0; for i in 0..n { while d[i] != i + 1 { let current = d[i] - 1; swap!(d[i], d[current]); counter += 1; } } let is_feasible = counter == k || (k > counter && (k - counter) % 2 == 0); write!(writer, "{}", if is_feasible { "YES" } else { "NO" }); } #[cfg(test)] mod tests { use super::*; #[test] fn sample1() { assert_judge!(process, " 2 1 2 1 ", "YES"); } #[test] fn sample2() { assert_judge!(process, " 3 2 3 2 1 ", "NO"); } #[test] fn sample3() { assert_judge!(process, " 4 2 1 2 3 4 ", "YES"); } }