Cpp-Leetcode题解之第88题合并两个有序数组.zip

# [88. Merge Sorted Array (Easy)](https://leetcode.com/problems/merge-sorted-array/) <p>You are given two integer arrays <code>nums1</code> and <code>nums2</code>, sorted in <strong>non-decreasing order</strong>, and two integers <code>m</code> and <code>n</code>, representing the number of elements in <code>nums1</code> and <code>nums2</code> respectively.</p> <p><strong>Merge</strong> <code>nums1</code> and <code>nums2</code> into a single array sorted in <strong>non-decreasing order</strong>.</p> <p>The final sorted array should not be returned by the function, but instead be <em>stored inside the array </em><code>nums1</code>. To accommodate this, <code>nums1</code> has a length of <code>m + n</code>, where the first <code>m</code> elements denote the elements that should be merged, and the last <code>n</code> elements are set to <code>0</code> and should be ignored. <code>nums2</code> has a length of <code>n</code>.</p> <p>&nbsp;</p> <p><strong>Example 1:</strong></p> <pre><strong>Input:</strong> nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3 <strong>Output:</strong> [1,2,2,3,5,6] <strong>Explanation:</strong> The arrays we are merging are [1,2,3] and [2,5,6]. The result of the merge is [<u>1</u>,<u>2</u>,2,<u>3</u>,5,6] with the underlined elements coming from nums1. </pre> <p><strong>Example 2:</strong></p> <pre><strong>Input:</strong> nums1 = [1], m = 1, nums2 = [], n = 0 <strong>Output:</strong> [1] <strong>Explanation:</strong> The arrays we are merging are [1] and []. The result of the merge is [1]. </pre> <p><strong>Example 3:</strong></p> <pre><strong>Input:</strong> nums1 = [0], m = 0, nums2 = [1], n = 1 <strong>Output:</strong> [1] <strong>Explanation:</strong> The arrays we are merging are [] and [1]. The result of the merge is [1]. Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1. </pre> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>nums1.length == m + n</code></li> <li><code>nums2.length == n</code></li> <li><code>0 &lt;= m, n &lt;= 200</code></li> <li><code>1 &lt;= m + n &lt;= 200</code></li> <li><code>-10⁹ &lt;= nums1[i], nums2[j] &lt;= 10⁹</code></li> </ul> <p>&nbsp;</p> <p><strong>Follow up: </strong>Can you come up with an algorithm that runs in <code>O(m + n)</code> time?</p> **Related Topics**: [Array](https://leetcode.com/tag/array/), [Two Pointers](https://leetcode.com/tag/two-pointers/), [Sorting](https://leetcode.com/tag/sorting/) **Similar Questions**: * [Merge Two Sorted Lists (Easy)](https://leetcode.com/problems/merge-two-sorted-lists/) * [Squares of a Sorted Array (Easy)](https://leetcode.com/problems/squares-of-a-sorted-array/) * [Interval List Intersections (Medium)](https://leetcode.com/problems/interval-list-intersections/) ## Solution 1. ```cpp // OJ: https://leetcode.com/problems/merge-sorted-array/ // Author: github.com/lzl124631x // Time: O(M + N) // Space: O(1) class Solution { public: void merge(vector<int>& A, int m, vector<int>& B, int n) { for (int i = m - 1, j = n - 1, k = m + n - 1; k >= 0; --k) { if (j < 0 || (i >= 0 && A[i] > B[j])) A[k] = A[i--]; else A[k] = B[j--]; } } }; ```