Java Utililty Methods Set Cardinality

List of utility methods to do Set Cardinality

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Description

The list of methods to do Set Cardinality are organized into topic(s).

Method

intcardinality(byte b)
cardinality 
int count = 0;
for (int i = 0; i < 8; ++i) {
    if (((b >>> i) & 1) == 1) {
        ++count;
return count;
intcardinality(final int from, final int to, final long[] words)
cardinality 
int sum = 0;
for (int i = from; i < to; i++) {
    sum += Long.bitCount(words[i]);
return sum;
intcardinality(long v)
Compute the cardinality (number of set bits) 
return Long.bitCount(v);
intcardinalityInBitmapRange(long[] bitmap, int start, int end)
Hamming weight of the bitset in the range start, start+1,..., end-1 
if (start >= end) {
    return 0;
int firstword = start / 64;
int endword = (end - 1) / 64;
if (firstword == endword) {
    return Long.bitCount(bitmap[firstword] & ((~0L << start) & (~0L >>> -end)));
int answer = Long.bitCount(bitmap[firstword] & (~0L << start));
for (int i = firstword + 1; i < endword; i++) {
    answer += Long.bitCount(bitmap[i]);
answer += Long.bitCount(bitmap[endword] & (~0L >>> -end));
return answer;
intcardinalityInBitmapWordRange(long[] bitmap, int start, int end)
Hamming weight of the 64-bit words involved in the range start, start+1,..., end-1 
if (start == end) {
    return 0;
int firstword = start / 64;
int endword = (end - 1) / 64;
int answer = 0;
for (int i = firstword; i <= endword; i++) {
    answer += Long.bitCount(bitmap[i]);
...