题解 | #只出现一次的数字(二)#

class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param nums int整型vector
     * @return int整型
     */
    int singleNumber(vector<int>& nums) {
        // write code here
        int ones = 0, twos = 0;
        for (int num : nums) {
            ones = (ones ^ num) &
                   ~twos;  // Add new number to ones if it's not already in twos
            twos = (twos ^ num) &
                   ~ones;  // Add new number to twos if it's not already in ones
        }
        return ones;  // The number that appears only once
    }
};