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 = 0;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;
    }
};