Leetcode 219 Contains Duplicate II STL

找出是否存在nums[i]==nums[j]，使得 j - i <=k

这是map的一个应用

 class Solution {
 public:
     bool containsNearbyDuplicate(vector<int>& nums, int k) {
         map<int,int> mii;
         for (int i = ;i<nums.size() ;++i)
         {
             if (mii.find(nums[i]) != mii.end())
             {
                 if(i - mii[nums[i]] <= k) return true;
             }
             mii[nums[i]] = i;
         }
         return false;
     }
 };