Cacher is the code snippet organizer for pro developers

/*
XOR:
　　1. a ^ b = b ^ a
　　4. a ^ a = 0.
　　5. 0 ^ a = a.
*/

class Solution {
    public int singleNumber(int[] nums) {
        int res = 0;

        int len = nums.length;
        for(int i = 0; i < len; i++)
            res ^= nums[i];

        return res;

    }
}