subsets

Every subset of items (the power set), including the empty one and items itself.

Subsets are ordered by the bit pattern that selects them (bit i set means items[i] is in), so the empty subset comes first and items itself last, and the elements of each subset keep their original order. The number of subsets doubles with every item, so more than MAX_SUBSET_ITEMS items are refused.

Import

use helpers4::set::subsets;

Cargo feature set (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features set

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.6", default-features = false, features = ["set"] }

Signature

pub fn subsets<T: Clone>(items: &[T]) -> Option<Vec<Vec<T>>>

Parameters

Parameter	Type	Description
items	&[T]	The elements to choose from.

Returns

Option<Vec<Vec<T>>> — The 2^n subsets, or None when items has more than MAX_SUBSET_ITEMS elements.

Examples

use helpers4::set::subsets;

assert_eq!(
    subsets(&["a", "b"]),
    Some(vec![vec![], vec!["a"], vec!["b"], vec!["a", "b"]])
);
assert_eq!(subsets(&[0; 17]), None);

Source

src/set/subsets.rs