leetcode

contains-duplicateV2.dart (941B)

---

 //This is a better solution to the problem. 
 //find any repeating integers in the list where
 //the absolute value of the index is less than or equal to 
 //k. To do this I added previous values to a map and checked them with
 //the newest one. If they meet the k rule then it returns true otherwise the
 //old value gets replaced. The time complexity of this code is O(n) where n is 
 //the length of the nums list. 
 //Time: 401ms Beats: 38.46%
 //Memory: 199.3MB Beats: 7.69%
 
 class Solution {
   bool containsNearbyDuplicate(List<int> nums, int k) {
       Map<int,int> previous_vals = {};
       for(int i = 0 ; i < nums.length ; ++i){
           if(previous_vals[nums[i]] == null){
               previous_vals[nums[i]] = i;
           }
           else if(((previous_vals[nums[i]] ?? 0) - i).abs() <= k){
               return true;
           }
           else{
               previous_vals[nums[i]] = i;
           }
       }
       return false;
   }
 }