Permutations by swapping: Difference between revisions
m
Minor edit to Rust code
m (Added link to WP page on Heap's algorithm. The pseudocode presented on that page has been corrected since this task was created.) |
m (Minor edit to Rust code) |
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Line 2,802:
<lang rust>// Implementation of Heap's algorithm.
// See https://en.wikipedia.org/wiki/Heap%27s_algorithm#Details_of_the_algorithm
fn generate<T, F>(a: &mut [T],
where
F:
{
let n = a.len();
let mut c = vec![0; n];
let mut i = 1;
while i < n {
if c[i] < i {
Line 2,817 ⟶ 2,818:
a.swap(c[i], i);
}
output(a, sign);
c[i] += 1;
i = 1;
Line 2,827 ⟶ 2,829:
}
fn
▲ generate(a, p);
}
Line 2,839 ⟶ 2,836:
println!("Permutations and signs for three items:");
let mut a = vec![0, 1, 2];
println!("\nPermutations and signs for four items:");
let mut b = vec![0, 1, 2, 3];
}</lang>
{{out}}
<pre>
▲[0, 1, 2] +1
[1, 0, 2] -1
[2, 0, 1]
[0, 2, 1] -1
[1, 2, 0]
[2, 1, 0] -1
Permutations and signs for four items:
[0, 1, 2, 3]
[1, 0, 2, 3] -1
[2, 0, 1, 3]
[0, 2, 1, 3] -1
[1, 2, 0, 3]
[2, 1, 0, 3] -1
[3, 1, 0, 2]
[1, 3, 0, 2] -1
[0, 3, 1, 2]
[3, 0, 1, 2] -1
[1, 0, 3, 2]
[0, 1, 3, 2] -1
[0, 2, 3, 1]
[2, 0, 3, 1] -1
[3, 0, 2, 1]
[0, 3, 2, 1] -1
[2, 3, 0, 1]
[3, 2, 0, 1] -1
[3, 2, 1, 0]
[2, 3, 1, 0] -1
[1, 3, 2, 0]
[3, 1, 2, 0] -1
[2, 1, 3, 0]
[1, 2, 3, 0] -1
</pre>
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