88. Merge Sorted Array - https://leetcode.com/problems/merge-sorted-array/description/

merge.java

class Solution {
    
    public void merge(int[] nums1, int m, int[] nums2, int n) {
        
        int capacity = m + n;

        for(int i = capacity -1; i >= 0; i--) {

            if(n < 1) {
                return;
            }

            if(m < 1) {
                nums1[i] = nums2[--n];
                continue;
            }

            if(nums1[m - 1] > nums2[n - 1]) {
                nums1[i] = nums1[--m];
            }
            else {
                nums1[i] = nums2[--n];
            }
        }
    }
}