Valid Word Square

Problem

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).

Constraints

• 1 <= words.length <= 500
• 1 <= words[i].length <= 500
• words[i] consists of only lowercase English letters.

Solution

The problem Valid Word Square can be solved by iterating through all characters in all given strings while checking if a diagonal character can exists, and if so, then if they are identical.

Implementation

class Solution
{
  public:
    bool validWordSquare(vector<string> &words)
    {
        for (int i = 0; i < words.size(); i++)
            for (int j = 0; j < words[i].length(); j++)
                if (words.size() <= j || words[j].length() <= i || words[i][j] != words[j][i])
                    return false;

        return true;
    }
};