Function malachite_base::slices::random_slice_permutations

source · [−]

pub fn random_slice_permutations<T>(
    seed: Seed, 
    xs: &[T]
) -> RandomSlicePermutations<'_, T>ⓘNotable traits for RandomSlicePermutations<'a, T>impl<'a, T> Iterator for RandomSlicePermutations<'a, T>    type Item = Vec<&'a T>;

Expand description

Uniformly generates a random permutation of references to a slice.

The iterator cannot outlive the slice. It may be more convenient for the iterator to own the data, in which case you may use random_vec_permutations instead.

The output length is infinite.

$P(p) = 1/n!$, where $n$ is xs.len().

Expected complexity per iteration

$T(n) = O(n)$

$M(n) = O(n)$

where $T$ is time, $M$ is additional memory, and $n$ is xs.len().

Examples

extern crate itertools;

use itertools::Itertools;
use malachite_base::random::EXAMPLE_SEED;
use malachite_base::slices::random_slice_permutations;

let css: Vec<String> = random_slice_permutations(EXAMPLE_SEED, &['a', 'b', 'c', 'd'])
    .take(20)
    .map(|ds| ds.into_iter().copied().collect())
    .collect();
assert_eq!(
    css.iter().map(String::as_str).collect_vec().as_slice(),
    [
        "cadb", "cbad", "cadb", "badc", "acdb", "cbad", "dabc", "dbca", "cdba", "cdab", "bacd",
        "cabd", "adbc", "cdab", "dcab", "abcd", "abcd", "dacb", "bcad", "adcb"
    ]
);