Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and jis at most k.

 

 to see which companies asked this question

 

bool containsNearbyDuplicate(vector
      
       & nums, int k) {    unordered_map
       
         hash;    int i = 0;    for (auto num : nums)    {        unordered_map
        
         ::iterator iter = hash.find(num);        if (iter == hash.end())            hash.insert(make_pair(num, i));        else {            if (i - (*iter).second <= k)                return true;            (*iter).second = i;        }        ++i;    }    return false;}