Given an array of strings words, return true if it forms a valid word square.
A sequence of strings forms a valid word square if the kth row and column read the same string, where 0 <= k < max(numRows, numColumns).
Given an array of strings words, return true if it forms a valid word square.
A sequence of strings forms a valid word square if the kth row and column read the same string, where 0 <= k < max(numRows, numColumns).