Crate derangements 

Derangements

derangements allows you to derange iterables: permutations where no element equals its index

Examples

use std::collections::HashMap;
use itertools::{assert_equal, Itertools};
use derangements::{derangements, restricted_permutations_by_map_value};
assert_equal(derangements(vec![0usize, 1, 2].into_iter(), 3).sorted(), [[1, 2, 0], [2, 0, 1]]);

// The module also contains other variants of restricted permutations
// Exclude from value 0 from indices 0 and 1, and value 1 from indices 1 and 2.
let restrict = HashMap::from([(0, vec![0, 1]), (1, vec![1, 2])]);
assert_equal(restricted_permutations_by_map_value(vec![0, 1, 2, 3].into_iter(), 3, restrict).sorted(),
   [[1, 2, 0], [1, 2, 3], [1, 3, 0], [1, 3, 2], [2, 3, 0], [3, 2, 0]]);

Functions

derangements

Derange k or all elements of an iterable.

derangements_range

Derange all elements of a range of 0 to n (non-inclusive).

derangements_range_fast

Derange all elements of a range of 0 to n (non-inclusive) with caching.

distinct_derangements

Derange k or all elements of an iterable without repetitions.

distinct_permutations

Permute k or all elements of an iterable without repetitions.

fast_permutations

Permute k or all elements of an iterable.

restricted_permutations

Permute k or all elements of an iterable while excluding based on an input restriction

restricted_permutations_by_map_index

Permute k or all elements of an iterable while excluding based on an input restriction

restricted_permutations_by_map_value

Permute k or all elements of an iterable while excluding based on an input restriction

restricted_permutations_by_self

Permute k or all elements of an iterable while excluding any results where one of the elements doesn’t change.