leetcode Merge Sorted Array 合并有序数组

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 nums1 and nums2 are m and n respectively.

题意：将两个有序数组合并到第一个数组中，第一个数组空间足够，合并后数组有序。
思路：从数组尾开始遍历，依次插如第一个数组，其中，第一个数组中元素先遍历完的情况单独考虑。

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