Leetcode - Array - 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 andn respectively.

class Solution {public:    void merge(int A[], int m, int B[], int n) {    if(A==NULL||m<0||B==NULL||n<0)    return;    reverse(A,A+m+n);    reverse(A+n,A+m+n);    int indexA=n,indexB=0,index=0;    while(indexA<m+n&&indexB<n)    {    if(A[indexA]<=B[indexB])    A[index++]=A[indexA++];    else    A[index++]=B[indexB++];    }    while(indexB<n)    A[index++]=B[indexB++];    }};