Word Squares II

Description

You are given a string array words, consisting of distinct 4-letter strings, each containing lowercase English letters.

A word square consists of 4 distinct words: top, left, right and bottom, arranged as follows:

- top forms the top row.

- bottom forms the bottom row.

- left forms the left column (top to bottom).

- right forms the right column (top to bottom).

It must satisfy:

- top[0] == left[0], top[3] == right[0]

- bottom[0] == left[3], bottom[3] == right[3]

Return all valid distinct word squares, sorted in ascending lexicographic order by the 4-tuple (top, left, right, bottom)​​​​​​​.