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 k = m+n-1;
        int i = m-1;
        int j = n -1;
        while(k >= 0 ){
            if(i < 0){
                A[k--] = B[j--];
            }
            else if(j < 0){
                A[k--] = A[i--];
            }else{
                if(A[i] > B[j]){
                    A[k--] = A[i--];
                }else{
                    A[k--] = B[j--];
                }
            }
        }
    }
};