A hash table is an efficient data structure to store and access data via keys. In this problem, you need to find the longest subarray of distinct elements. For example, given an array A = , the longest subarray is . Hint: you need to keep track and update the positions of the elements.

(1) (0.5 point) Explain how many unique subarrays are there from a given array; (2) (1 point) Describe your ideas on how to solve the problem, especially how hash tables can be used to keep track of the important information; (2) (1.5 points) Write the most efficient algorithm (pseudo code) to solve this problem with complexity analysis. You can assume that a good hash function is given.