題目
Given a list of unique words, find all pairs of distinct indices (i,
j)
in the given list, so that the concatenation of the two words, i.e.words[i] + words[j]
is
a palindrome.
Example 1:
Given words
= ["bat",
"tab", "cat"]
Return [[0, 1], [1, 0]]
The palindromes are ["battab", "tabbat"]
Example 2:
Given words
= ["abcd",
"dcba", "lls", "s", "sssll"]
Return [[0, 1], [1, 0], [3, 2], [2, 4]]
The palindromes are ["dcbaabcd", "abcddcba", "slls", "llssssll"]