use std::io; use std::io::{BufRead, Write}; use std::collections::vec_deque::VecDeque; use std::cmp::min; 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) } } } }); } fn main() { let stdio = io::stdin(); let input = stdio.lock(); let output = io::stdout(); process(input, output); } // 1: 0001 // 2: 0010 // 3: 0011 // 5: 0101 // 7: 0111 //10: 1010 // 8: 1000 // 9: 1001 //11: 1011 fn count_bit(n: usize) -> usize { let mut c = 0; for i in 0..32 { c += (n >> i) & 1_usize; } c } fn process(mut reader: R, mut writer: W) -> () where R: BufRead, W: Write { input! { stdin = reader, n: usize } // breadth first search let mut points = [None; 10001]; points[1] = Some(1); let mut queue = VecDeque::new(); queue.push_back(1); while let Some(current) = queue.pop_front() { let current_hops = points[current].unwrap(); let n_steps = count_bit(current); if n_steps < current { // 0 < current - n_steps let next = current - n_steps; match points[next] { Some(i) => { points[next] = Some(min(i, current_hops + 1)); } None => { points[next] = Some(current_hops + 1); queue.push_back(next); } } } if current + n_steps <= n { let next = current + n_steps; match points[next] { Some(i) => { points[next] = Some(min(i, current_hops + 1)); } None => { if next == n { write!(writer, "{}", current_hops + 1); return; } points[next] = Some(current_hops + 1); queue.push_back(next); } } } } write!(writer, "-1"); } #[cfg(test)] mod tests { use super::*; #[test] fn sample1() { assert_judge!(process, "5", "4"); } #[test] fn sample2() { assert_judge!(process, "11", "9"); } #[test] fn sample3() { assert_judge!(process, "4", "-1"); } }