<p>You are given an integer array <code>nums</code> and an integer <code>k</code>.</p> <p>In one operation, you can pick two numbers from the array whose sum equals <code>k</code> and remove them from the array.</p> <p>Return <em>the maximum number of operations you can perform on the array</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> nums = [1,2,3,4], k = 5 <strong>Output:</strong> 2 <strong>Explanation:</strong> Starting with nums = [1,2,3,4]: - Remove numbers 1 and 4, then nums = [2,3] - Remove numbers 2 and 3, then nums = [] There are no more pairs that sum up to 5, hence a total of 2 operations.</pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> nums = [3,1,3,4,3], k = 6 <strong>Output:</strong> 1 <strong>Explanation:</strong> Starting with nums = [3,1,3,4,3]: - Remove the first two 3's, then nums = [1,4,3] There are no more pairs that sum up to 6, hence a total of 1 operation.</pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= nums.length <= 10<sup>5</sup></code></li> <li><code>1 <= nums[i] <= 10<sup>9</sup></code></li> <li><code>1 <= k <= 10<sup>9</sup></code></li> </ul>