136. 只出现一次的数字

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        res = 0
        for num in nums:
            res ^= num
        return res

class Solution {
    public int singleNumber(int[] nums) {
        int res = 0;
        for (int num : nums) {
            res ^= num;
        }
        return res;
    }
}

/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNumber = function (nums) {
  let res = 0;
  for (let num of nums) {
    res ^= num;
  }
  return res;
};

func singleNumber(nums []int) int {
	res := 0
	for _, v := range nums {
		res ^= v
	}
	return res
}

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