All possible subsets of a set using bit manipulations in Java -

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how can generate possible subsets of set using bit manipulations in java? example, if have int array [1, 2, 3], possible subsets are:

[               [3],          [1],          [2],          [1,2,3],      [1,3],        [2,3],        [1,2],        []          ]

count 0 (2set.size() - 1) (inclusive). retrieve elements corresponding 1 bits in current count. set have ordered retrieve elements index, of course.

the tricky part pulling out elements corresponding 1 bits in current count. here's pseudocode 1 way that:

for (int pos = 0, mask = 1; mask <= currentcount; mask <<= 1; ++pos) {     if ((currentcount & mask) != 0) {         include element @ pos in current subset     } }

note assumes original set size no more number of bits available whatever integer type using count , mask.


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