pub fn select_ones(
index: &[u64],
all_bits: BitsRef<'_>,
target_rank: u64,
) -> Option<u64>Expand description
Find the position of a set bit by its rank using the index (O(log n)).
Returns None if no suitable bit is found. It is
always the case otherwise that rank_ones(index, result) == Some(target_rank)
and get(result) == Some(true).