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combinations

use_math

Function combinations 

Source 
pub fn combinations(n: u64, k: u64) -> Result<u128, CombinatoricsError>
Expand description

Returns the number of unordered selections of size k from n items.

§Errors

Returns CombinatoricsError::KExceedsN when k > n.

Returns CombinatoricsError::CombinationOverflow when the result no longer fits in u128.

§Examples

use use_combinatorics::combinations;

assert_eq!(combinations(5, 2)?, 10);
Examples found in repository?
examples/facade_combinatorics.rs (line 6)
3fn main() -> Result<(), use_math::CombinatoricsError> {
4    assert_eq!(factorial(5)?, 120);
5    assert_eq!(permutations(5, 3)?, 60);
6    assert_eq!(combinations(5, 2)?, 10);
7
8    Ok(())
9}