LeetCode 219. Contains Duplicate II

[code]class Solution {
public boolean containsNearbyDuplicate(int[] nums, int k) {
// Corner Case
if(nums == null || nums.length == 0){
return false;
}
Map<Integer, Integer> seen = new HashMap<>();
for(int i = 0; i < nums.length; i++){
if(seen.containsKey(nums[i])){
if(i - seen.get(nums[i]) <= k){
return true;
}
}
// Add or update the value
seen.put(nums[i], i);
}
return false;
}
}