Get all Indexes of the set bits in a BitSet

bitset, java

Solution

No need to use `bitSet.cardinality()` at all:

for (int i = bitSet.nextSetBit(0); i != -1; i = bitSet.nextSetBit(i + 1)) {
    indexes.add(i);
}

Problem

I'm looking for a fast algorithm with gives me all the indexes of the set bits in a BitSet object. This is slow: ``` BitSet bitSet = ... Collection<Integer> indexes = new ArrayList<Integer>(bitSet.cardinality()); int nextSetBit = bitSet.nextSetBit(0); for (int i = 0; i < bitSet.cardinality(); ++i ) { indexes.add(nextSetBit); nextSetBit = bitSet.nextSetBit(nextSetBit + 1); } ... ``` Any help is appreciated!

Original source