SingleNumberIII.cpp

/*Given an array of numbers nums, in which exactly two elements appear only once and 
 *all the other elements appear exactly twice. Find the two elements that appear only once.
 *
 *For example:
 *
 *Given nums = [1, 2, 1, 3, 2, 5], return [3, 5].
 *
 *Note:
 *The order of the result is not important. So in the above example, [5, 3] is also correct.
 *Your algorithm should run in linear runtime complexity. Could you implement it using only constant space complexity?
*/

class Solution {
public:
    vector<int> singleNumber(vector<int>& nums) {
        vector<int> result{0,0};
        int diff=accumulate(nums.begin(),nums.end(),0,bit_xor<int>());
        diff&=-diff;
        for(int num:nums)
        {
            if((num&diff)==0)
                result[0]^=num;
            else
                result[1]^=num;
        }
        return result;
    }
};