Exclusive or between N bit sets

Question

I am implementing a program in Java using BitSets and I am stuck in the following operation: Given N BitSets return a BitSet with 0 if there is more than 1 one in all the BitSets, and 1 otherwise As an example, suppose we have this 3 sets: - 10010 - 01011 00111 11100 expected result For the following sets : - 10010 - 01011 - 00111 - 10100 00101 01000 expected result I am trying to do this exclusive with bit wise operations, and I have realized that what I need is literally the exclusive or between all the sets, but not in an iterative fashion, so I am quite stumped with what to do. Is this even possible? I wanted to avoid the costly solution of having to check each bit in each set, and keep a counter for each position... Thanks for any help Edit : as some people asked, this is part of a project I'm working on. I am building a time table generator and basically one of the soft constraints is that no student should have only 1 class in 1 day, so those Sets represent the attending studen…

Accepted Answer

You can do what you want with two values. One has the bits set at least once, the second has those set more than once. The combination can be used to determine those set once and no more.

```
int[] ints = {0b10010, 0b01011, 0b00111, 0b10100, 0b00101};
int setOnce = 0, setMore = 0;
for (int i : ints) {
    setMore |= setOnce & i;
    setOnce |= i;
}
int result = setOnce & ~setMore;
System.out.println(String.format("%5s", Integer.toBinaryString(result)).replace(' ', '0'));
```

prints

```
01000
```

Exclusive or between N bit sets

Solution

Problem