Contains Duplicate III
problem
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.
how to solve
To solve this problem, I use set(binary search tree). In set, the value is sorted automatically and I can insert and delete in O(logn). We can check the most near higher element and the most near lower element in O(logn) using lower_bound. So we can get answer in O(nlogn).
