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 absolute difference
between nums[i] and nums[j] is
at most t and
the absolute difference
between i and j is
at most k.

bool containsNearbyAlmostDuplicate(vector<int>& nums, int k, int t)
{
if (!k || t<0 || nums.size()<2)
return false;
set<int>record;
auto nLen = nums.size();
for (int i = 0; i < nLen;++i)
{
if (i>k)
record.erase(nums[i - k - 1]);
set<int>::iterator lower = record.lower_bound(nums[i] - t);
if (lower != record.end() && abs(nums[i] - *lower) <= t)
return true;

record.insert(nums[i]);
}
return false;
}