220. Contains Duplicate III

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

1. there is no need for the window to be fully sorted, so uses a treeset to partially sort the window.
2. if the next index exceed the window side, remove the frist window element.

public class Solution {
    public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
        if(k < 1 || t <0 || nums == null || nums.length < 2) return false;
        SortedSet<Long> set = new TreeSet<>();
        for(int j=0; j<nums.length; j++){

            SortedSet<Long> sub = set.subSet((long)nums[j] -t , (long)nums[j] + t+1);
            if(!sub.isEmpty()) return true;


            if(j>=k){
                set.remove((long)nums[j-k]);
            }

            set.add((long)nums[j]);
        }

        return false;
    }
}