<p>Write a method to return all subsets of a set. The elements in a set are pairwise distinct.</p> <p>Note: The result set should not contain duplicated subsets.</p> <p><strong>Example:</strong></p> <pre> <strong> Input</strong>: nums = [1,2,3] <strong> Output</strong>: [ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ] </pre>