You are given an array of strings words.

Let us define a boolean function isPrefixAndSuffix(str1, str2) that returns true if str1 is both a prefix and a suffix of str2, and false otherwise.

Return the total number of index pairs (i, j) such that $i < j$ and isPrefixAndSuffix(words[i], words[j]) is true.

Constraints:

• $1 \leq$ words.length $\leq 10^5$

• $1 \leq$ words[i].length $\leq 10^5$

• words[i] consists only of lowercase English letters.

• The sum of the lengths of all words[i] does not exceed $5 imes 10^5$.

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.