fork download
copy 
  1. // author: Leonardone @ NEETSDKASU
  2.  
  3. struct Comb {
  4.     size: usize,
  5.     x: Vec<usize>,
  6.     init: bool,
  7. }
  8.  
  9. impl Comb {
  10.     fn new(size: usize, sel: usize) -> Self {
  11.         Self {
  12.             size,
  13.             x: vec![0; sel],
  14.             init: false,
  15.         }
  16.     }
  17.     fn next(&mut self) -> Option<&[usize]> {
  18.         if !self.init {
  19.             self.init = true;
  20.             self.x.iter_mut().enumerate().for_each(|(i, e)| *e = i);
  21.             return Some(&self.x);
  22.         }
  23.         let mut i = self.x.len() - 1;
  24.         let mut k = self.size - 1;
  25.         loop {
  26.             self.x[i] += 1;
  27.             if self.x[i] > k {
  28.                 if i == 0 {
  29.                     self.init = false;
  30.                     return None;
  31.                 }
  32.                 i -= 1;
  33.                 k -= 1;
  34.             } else {
  35.                 while i + 1 < self.x.len() {
  36.                     self.x[i + 1] = self.x[i] + 1;
  37.                     i += 1;
  38.                 }
  39.                 return Some(&self.x);
  40.             }
  41.         }
  42.     }
  43. }
  44.  
  45. fn main() {
  46.     let mut c = Comb::new(5, 3);
  47.     while let Some(x) = c.next() {
  48.         println!("{:?}", x);
  49.     }
  50. }
  51.  
Success #stdin #stdout 0s 4424KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
[0, 1, 2]
[0, 1, 3]
[0, 1, 4]
[0, 2, 3]
[0, 2, 4]
[0, 3, 4]
[1, 2, 3]
[1, 2, 4]
[1, 3, 4]
[2, 3, 4]
https://ideone.com/hrKnzS
Rust comb
language:
Rust (rust 1.56)
created:
3 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!