Merge Sorted Array

Given two sorted integer arrays A and B, merge B into A as one sorted array.

Note:

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

Merge element into the length (m+n) of array A.

public void merge(int A[], int m, int B[], int n) {
        //merged array index
        int k = m+n-1;
        //A index
        int i = m-1;
        //B index
        int j = n-1;

        //the idea behind is merge from the end elements of two arrays;
        while (i>=0 && j>=0) {
            if (A[i]>=B[j]) {
                A[k--] = A[i--];
            } else {
                A[k--] = B[j--];
            }
        }

        //A won't have left over, either element's in A is already in array A or B has left over need to merge into A
        //A[1,2,3, , ,]  B[7,8,9] -> [1,2,3,7,8,9]
        //A[7,8,9, , ,]  B[1,2,3] -> [7,8,9,7,8,9]
        while (j>=0) {
            A[k--] = B[j--];
        }

    }