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 to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

 

public class Solution {
    public void merge(int A[], int m, int B[], int n) {
        //index指向两个数组的末尾
        int i=m-1;
        int j=n-1;
        //合并以后最后一个元素的lastIndex为m+n-1
        int index = m+n-1;
        //从后向前合并
        while (i>=0&&j>=0) {
            if (A[i]>B[j]) {
                A[index--] = A[i--];
            } else {
                A[index--] = B[j--];
            }
        }
        while (j>=0) {
            A[index--] = B[j--];
        }
    }
}