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.

用一个双层循环明显超时。

别人用同样的时间O(nlog(k))，但是用TreeSet实现。TreeSet具有排序功能，能够

返回在某个区间的set。

public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
	if(k<1||t<0)
		return false;
	TreeSet<Long> set=new TreeSet<>();
	for(int i=0;i<nums.length;i++){
		long left=(long)nums[i]-t;
		long right=(long)nums[i]+t+1;
		SortedSet<Long> subSet=set.subSet(left, right);
		if(!subSet.isEmpty())
			return true;
		set.add((long) nums[i]);
		if(i>=k)
			set.remove((long)nums[i-k]);
	}
	return false;
}