<p>Given an array <code>nums</code> of integers, we need to find the maximum possible sum of elements of the array such that it is divisible by three.</p> <ol> </ol> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> nums = [3,6,5,1,8] <strong>Output:</strong> 18 <strong>Explanation:</strong> Pick numbers 3, 6, 1 and 8 their sum is 18 (maximum sum divisible by 3).</pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> nums = [4] <strong>Output:</strong> 0 <strong>Explanation:</strong> Since 4 is not divisible by 3, do not pick any number. </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> nums = [1,2,3,4,4] <strong>Output:</strong> 12 <strong>Explanation:</strong> Pick numbers 1, 3, 4 and 4 their sum is 12 (maximum sum divisible by 3). </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= nums.length <= 4 * 10^4</code></li> <li><code>1 <= nums[i] <= 10^4</code></li> </ul>