<p>The <strong>n-queens</strong> puzzle is the problem of placing <code>n</code> queens on an <code>n x n</code> chessboard such that no two queens attack each other.</p>
<p>Given an integer <code>n</code>, return <em>all distinct solutions to the <strong>n-queens puzzle</strong></em>. You may return the answer in <strong>any order</strong>.</p>
<p>Each solution contains a distinct board configuration of the n-queens' placement, where <code>'Q'</code> and <code>'.'</code> both indicate a queen and an empty space, respectively.</p>
