56.1.数组中数字出现的次数 (Medium)*

class Solution {
public:
    vector<int> singleNumbers(vector<int>& nums) {
        int res = 0 ;
        for(auto& num : nums) {
            res ^= num;
        }
        int mask = res & (-res);
        int a = 0, b = 0;
        for(auto& num : nums) {
            if(mask & num) {
                a ^= num;
            }else {
                b ^= num;
            }
        }
        return {a, b};
    }
};