LeetCode之“散列表”：Single Number

　　题目链接

　　题目要求：

　　Given an array of integers, every element appears twice except for one. Find that single one.

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

　　这道题属于比较简单的，程序如下：

 class Solution {
 public:
     int singleNumber(vector<int>& nums) {
         unordered_map<int, int> hashMap;
         int sz = nums.size();
         for(int i = ; i < sz; i++)
             hashMap[nums[i]]++;

         unordered_map<int, int>::iterator itr = hashMap.begin();
         for(; itr != hashMap.end(); itr++)
         {
             if(itr->second == )
                 return itr->first;
         }

         return INT_MIN;
     }
 };