| 1| |// compile-flags: -Zinline-mir | |
| 2| | | |
| 3| |use std::fmt::Display; | |
| 4| | | |
| 5| 1|fn main() { | |
| 6| 1| permutations(&['a', 'b', 'c']); | |
| 7| 1|} | |
| 8| | | |
| 9| |#[inline(always)] | |
| 10| 1|fn permutations<T: Copy + Display>(xs: &[T]) { | |
| 11| 1| let mut ys = xs.to_owned(); | |
| 12| 1| permutate(&mut ys, 0); | |
| 13| 1|} | |
| 14| | | |
| 15| 16|fn permutate<T: Copy + Display>(xs: &mut [T], k: usize) { | |
| 16| 16| let n = length(xs); | |
| 17| 16| if k == n { | |
| 18| 6| display(xs); | |
| 19| 10| } else if k < n { | |
| 20| 15| for i in k..n { | |
| ^10 | |
| 21| 15| swap(xs, i, k); | |
| 22| 15| permutate(xs, k + 1); | |
| 23| 15| swap(xs, i, k); | |
| 24| 15| } | |
| 25| 0| } else { | |
| 26| 0| error(); | |
| 27| 0| } | |
| 28| 16|} | |
| 29| | | |
| 30| 16|fn length<T>(xs: &[T]) -> usize { | |
| 31| 16| xs.len() | |
| 32| 16|} | |
| 33| | | |
| 34| |#[inline] | |
| 35| 30|fn swap<T: Copy>(xs: &mut [T], i: usize, j: usize) { | |
| 36| 30| let t = xs[i]; | |
| 37| 30| xs[i] = xs[j]; | |
| 38| 30| xs[j] = t; | |
| 39| 30|} | |
| 40| | | |
| 41| 6|fn display<T: Display>(xs: &[T]) { | |
| 42| 24| for x in xs { | |
| ^18 | |
| 43| 18| print!("{}", x); | |
| 44| 18| } | |
| 45| 6| println!(); | |
| 46| 6|} | |
| 47| | | |
| 48| |#[inline(always)] | |
| 49| 0|fn error() { | |
| 50| 0| panic!("error"); | |
| 51| 0|} | |