[LeetCode] Merge Sorted Array

Merge Sorted Array

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

Note:
You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1and nums2 are m and n respectively.

解題思路：

這道題與合並排序差不多，唯一不同的是不可以申請額外的空間。注意到第一個數組的實際空間長度是大於兩個數組長度之和的，因此，我們可以先把第一個數組的元素平移至末尾，然後按合並排序的步驟合並即可。

class Solution {
public:
    void merge(vector& nums1, int m, vector& nums2, int n) {
        //首先將nums1的元素後移至末尾
        int len1=nums1.size();
        for(int i=1; i<=m; i++){
            nums1[len1-i] = nums1[m-i];
        }
        int k=0;
        int i = len1 - m;
        int j = 0;
        while(i