<p>In an array of integers, a "peak" is an element which is greater than or equal to the adjacent integers and a "valley" is an element which is less than or equal to the adjacent inte­gers. For example, in the array {5, 8, 4, 2, 3, 4, 6}, {8, 6} are peaks and {5, 2} are valleys. Given an array of integers, sort the array into an alternating sequence of peaks and valleys.</p> <p><strong>Example:</strong></p> <pre> <strong>Input: </strong>[5, 3, 1, 2, 3] <strong>Output:</strong> [5, 1, 3, 2, 3] </pre> <p><strong>Note: </strong></p> <ul> <li><code>nums.length <= 10000</code></li> </ul>