You are given a 0-indexed array of unique strings words.
A palindrome pair is a pair of integers (i, j) such that:
0 <= i, j < words.length,i != j, andwords[i] + words[j] (the concatenation of the two strings) is a palindrome.Return an array of all the palindrome pairs of words.
You must write an algorithm with O(sum of words[i].length) runtime complexity.
\n
Example 1:
\n\n\nInput: words = ["abcd","dcba","lls","s","sssll"]\nOutput: [[0,1],[1,0],[3,2],[2,4]]\nExplanation: The palindromes are ["abcddcba","dcbaabcd","slls","llssssll"]\n\n\n
Example 2:
\n\n\nInput: words = ["bat","tab","cat"]\nOutput: [[0,1],[1,0]]\nExplanation: The palindromes are ["battab","tabbat"]\n\n\n
Example 3:
\n\n\nInput: words = ["a",""]\nOutput: [[0,1],[1,0]]\nExplanation: The palindromes are ["a","a"]\n\n\n
\n
Constraints:
\n\n1 <= words.length <= 50000 <= words[i].length <= 300words[i] consists of lowercase English letters.Compiled with clang 11 using the latest C++ 20 standard.
Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.
Most standard library headers are already included automatically for your convenience.
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