<p>Given a string array <code>words</code>, return <em>the maximum value of</em> <code>length(word[i]) * length(word[j])</code> <em>where the two words do not share common letters</em>. If no such two words exist, return <code>0</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> words = ["abcw","baz","foo","bar","xtfn","abcdef"] <strong>Output:</strong> 16 <strong>Explanation:</strong> The two words can be "abcw", "xtfn". </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> words = ["a","ab","abc","d","cd","bcd","abcd"] <strong>Output:</strong> 4 <strong>Explanation:</strong> The two words can be "ab", "cd". </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> words = ["a","aa","aaa","aaaa"] <strong>Output:</strong> 0 <strong>Explanation:</strong> No such pair of words. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 <= words.length <= 1000</code></li> <li><code>1 <= words[i].length <= 1000</code></li> <li><code>words[i]</code> consists only of lowercase English letters.</li> </ul>