Function iter_set::intersection

pub fn intersection<T, L, R>(
    a: L, 
    b: R
) -> impl Iterator<Item = T> where
    T: Ord,
    L: IntoIterator<Item = T>,
    R: IntoIterator<Item = T>, 

Take the intersection of two sets represented by sorted, deduplicated iterators.

The elements returned will all be from a.

Time complexity: O(a.len() + b.len()).