[LeetCode] Merge Sorted Array

A classic subroutine of merge sort. Just merge the elements from back to forth. Keep a pointer for the merged position of the element and two other pointers for elements in nums1 and nums2 respectively.

The code is as follows.

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        int p = m + n - 1, p1 = m - 1, p2 = n - 1;
        while (p1 >= 0 && p2 >= 0) {
            if (nums1[p1] >= nums2[p2])
                nums1[p--] = nums1[p1--];
            else nums1[p--] = nums2[p2--];
        }
        while (p2 >= 0)
            nums1[p--] = nums2[p2--];
    }
};