【LeetCode】137. Single Number II（C++）

Given a non-empty array of integers, every element appears three times except for one, which appears exactly once. Find that single one.

Note:

Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Example 1:

Input: [2,2,3,2]
Output: 3

Example 2:

Input: [0,1,0,1,0,1,99]
Output: 99

代码：

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int i;
        if(nums.size()==1)
            return nums[0];
        sort(nums.begin(), nums.end());
        for(i=0; i<nums.size()-2; i+=3)
        {
            if(nums[i]!=nums[i+1])
                return nums[i];
        }
        return nums[i]; 
    }
};