Merge Sorted Array

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