LeetCode (Single Number II)

Problem:

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

Solution:

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