【LeetCode】84. Merge Sorted Array

题目描述(Easy)

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

• The number of elements initialized in nums1 and nums2 are m and n respectively.
• You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

题目链接

https://leetcode.com/problems/merge-sorted-array/description/

Example 1:

Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3

Output: [1,2,2,3,5,6]

算法分析

从后往前合并。

提交代码：

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        int i = m - 1, j = n - 1, index = m + n - 1;
        
        while (i >=0 && j >= 0)
        {
            nums1[index--] = nums1[i] >= nums2[j] ? nums1[i--] : nums2[j--];
        }
        
        while (j >= 0)
            nums1[index--] = nums2[j--];
    }
};