LeetCode 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.

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

if (i >= 0)
while (i >= 0)
A[p--] = A[i--];
else
while (j >= 0)
A[p--] = B[j--];
}
};