回文对

给定一组互不相同的单词，找出所有不同的索引对 (i, j)，使得列表中的两个单词， words[i] + words[j] ，可拼接成回文串。

def f(words):

    def isPalindrome(s, i, j):
        return s[i:j] == s[i:j][::-1]

    data = {word[::-1]:i for i,word in enumerate(words)}

    def find(w):
        return data.get(w, -1)

    ans = []
    for i,word in enumerate(words):
        for j in range(len(words[i])):
            if isPalindrome(word, j, len(word)) and find(word[0:j]) != -1:
                ans.append([i, find(word[0:j])])
            if isPalindrome(word, 0, j) and find(word[j:]) != -1:
                ans.append([find(word[j:]), i])

    return ans


words = ["abcd","dcba","lls","s","sssll"]

print(f(words))