136. 只出现一次的数字

class Solution {
public:
  int singleNumber(vector<int>& nums) {
    int Result{};
    for (int X : nums)
      Result ^= X;
    return Result;
  }
};

class Solution {
public:
  int singleNumber(vector<int>& nums) {
    int Result = 0;
    for (int X : nums)
      Result ^= X;
    return Result;
  }
};