Count Prefix and Suffix Pairs I

lcpy gen -n 3042   # by problem number
lcpy gen -s count_prefix_and_suffix_pairs_i   # by problem name

Input: words = ["a","aba","ababa","aa"]
Output: 4
Explanation: In this example, the counted index pairs are:
i = 0 and j = 1 because isPrefixAndSuffix("a", "aba") is true.
i = 0 and j = 2 because isPrefixAndSuffix("a", "ababa") is true.
i = 0 and j = 3 because isPrefixAndSuffix("a", "aa") is true.
i = 1 and j = 2 because isPrefixAndSuffix("aba", "ababa") is true.
Therefore, the answer is 4.

Input: words = ["pa","papa","ma","mama"]
Output: 2
Explanation: In this example, the counted index pairs are:
i = 0 and j = 1 because isPrefixAndSuffix("pa", "papa") is true.
i = 2 and j = 3 because isPrefixAndSuffix("ma", "mama") is true.
Therefore, the answer is 2.

Input: words = ["abab","ab"]
Output: 0
Explanation: In this example, the only valid index pair is i = 0 and j = 1, and isPrefixAndSuffix("abab", "ab") is false.
Therefore, the answer is 0.

class Solution:
    # Time: O(n * m^2)
    # Space: O(1)
    def count_prefix_suffix_pairs(self, words: list[str]) -> int:
        count = 0
        for i, prefix in enumerate(words):
            for suffix in words[i + 1 :]:
                if suffix.startswith(prefix) and suffix.endswith(prefix):
                    count += 1
        return count