<p>Given a binary array <code>nums</code>, return <em>the maximum length of a contiguous subarray with an equal number of </em><code>0</code><em> and </em><code>1</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> nums = [0,1] <strong>Output:</strong> 2 <strong>Explanation:</strong> [0, 1] is the longest contiguous subarray with an equal number of 0 and 1. </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> nums = [0,1,0] <strong>Output:</strong> 2 <strong>Explanation:</strong> [0, 1] (or [1, 0]) is a longest contiguous subarray with equal number of 0 and 1. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= nums.length <= 10<sup>5</sup></code></li> <li><code>nums[i]</code> is either <code>0</code> or <code>1</code>.</li> </ul>