Merge Sorted Array

Given two sorted integer arrays A and B, merge B into A as one sorted array.
** Notice
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.
ExampleA = [1, 2, 3, empty, empty]
, B = [4, 5]
After merge, A will be filled as [1, 2, 3, 4, 5]

合并两个排序好的数组，而且题目说明数组A的side大于m+n; 所以我们用的方法就是从两个数组最后一个数字比起，大的就放到m+n-1的位置去，然后调整index之后继续比下去直到一个数组先空为止，在判断把另一个有剩余的数组填进去。

class Solution {
    /**
     * @param A: sorted integer array A which has m elements, 
     *           but size of A is m+n
     * @param B: sorted integer array B which has n elements
     * @return: void
     */
    public void mergeSortedArray(int[] A, int m, int[] B, int n) {
        // write your code here
        
        int i = m-1, j = n-1, k = m+n-1;
        while(i >= 0 && j >= 0){
            if(A[i] < B[j]){
                A[k] = B[j];
                k--;
                j--;
            }else{
                A[k] = A[i];
                k--;
                i--;
            }
        }
        
        while(i >= 0){
            A[k] = A[i];
            k--;
            i--;
        }
        
        while(j >= 0){
            A[k] = B[j];
            k--;
            j--;
        }
    }
}