<p>You are given two string arrays <code>words1</code> and <code>words2</code>.</p> <p>A string <code>b</code> is a <strong>subset</strong> of string <code>a</code> if every letter in <code>b</code> occurs in <code>a</code> including multiplicity.</p> <ul> <li>For example, <code>"wrr"</code> is a subset of <code>"warrior"</code> but is not a subset of <code>"world"</code>.</li> </ul> <p>A string <code>a</code> from <code>words1</code> is <strong>universal</strong> if for every string <code>b</code> in <code>words2</code>, <code>b</code> is a subset of <code>a</code>.</p> <p>Return an array of all the <strong>universal</strong> strings in <code>words1</code>. You may return the answer in <strong>any order</strong>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["e","o"] <strong>Output:</strong> ["facebook","google","leetcode"] </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["l","e"] <strong>Output:</strong> ["apple","google","leetcode"] </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= words1.length, words2.length <= 10<sup>4</sup></code></li> <li><code>1 <= words1[i].length, words2[i].length <= 10</code></li> <li><code>words1[i]</code> and <code>words2[i]</code> consist only of lowercase English letters.</li> <li>All the strings of <code>words1</code> are <strong>unique</strong>.</li> </ul>