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Solution: Palindrome Pairs

Explore how to detect all palindrome pairs in an array of unique words using a Trie. Understand the core cases for palindrome formation and efficiently implement solutions with reversed word insertions and palindrome checks to achieve optimal performance.

Statement

You are given a 0-indexed array of unique strings called words.

A palindrome pair is defined as a pair of indexes (i, j) where both i and j are within the valid range of the list of words (that is, 00 \leq i, j << words.length), and i is not equal to j. The key condition is that when the word at index i is concatenated with the word at index j (forming words[i] + words[j]), the resulting string must be a palindrome.

Your task is to return all valid palindrome pairs as a list of index pairs.

Additionally, your solution must have a time complexity of O(sum ofO(\text{sum of} words.length)).

Constraints:

  • 11 \leq words.length 1000\leq 1000

  • ...