<p>You are given two integer arrays <code>nums1</code> and <code>nums2</code> sorted in <strong>ascending order</strong> and an integer <code>k</code>.</p> <p>Define a pair <code>(u, v)</code> which consists of one element from the first array and one element from the second array.</p> <p>Return <em>the</em> <code>k</code> <em>pairs</em> <code>(u<sub>1</sub>, v<sub>1</sub>), (u<sub>2</sub>, v<sub>2</sub>), ..., (u<sub>k</sub>, v<sub>k</sub>)</code> <em>with the smallest sums</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> nums1 = [1,7,11], nums2 = [2,4,6], k = 3 <strong>Output:</strong> [[1,2],[1,4],[1,6]] <strong>Explanation:</strong> The first 3 pairs are returned from the sequence: [1,2],[1,4],[1,6],[7,2],[7,4],[11,2],[7,6],[11,4],[11,6] </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> nums1 = [1,1,2], nums2 = [1,2,3], k = 2 <strong>Output:</strong> [[1,1],[1,1]] <strong>Explanation:</strong> The first 2 pairs are returned from the sequence: [1,1],[1,1],[1,2],[2,1],[1,2],[2,2],[1,3],[1,3],[2,3] </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> nums1 = [1,2], nums2 = [3], k = 3 <strong>Output:</strong> [[1,3],[2,3]] <strong>Explanation:</strong> All possible pairs are returned from the sequence: [1,3],[2,3] </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= nums1.length, nums2.length <= 10<sup>5</sup></code></li> <li><code>-10<sup>9</sup> <= nums1[i], nums2[i] <= 10<sup>9</sup></code></li> <li><code>nums1</code> and <code>nums2</code> both are sorted in <strong>ascending order</strong>.</li> <li><code>1 <= k <= 10<sup>4</sup></code></li> </ul>