Given a list of words, find the number of prefix pairs, i.e. pairs i, j where words[i] == words[j] or words[i].startswith(words[j]) or words[j].startswith(words[i]).

To find the number of prefix pairs in a list of words, a straightforward approach is to iterate through all unique pairs of words and check if one is a prefix of the other using startswith(). For very large lists, a more efficient solution involves using a Trie data structure. Insert each word into the Trie, and during insertion, check for existing words that are prefixes of the current word or vice versa. This optimizes the prefix checking process, significantly reducing the time complexity compared to the naive pairwise comparison.