LeetCode 64 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.

分析：

归并排序的中间步骤，注意点是要把最后结果放在A里，为了不覆盖A中元素，要从后向前归并。

public class Solution {
public void merge(int A[], int m, int B[], int n) {

int index = m+n-1;
int aIndex = m-1;
int bIndex = n-1;
while(aIndex>=0 && bIndex>=0){
if(A[aIndex]>=B[bIndex]){
A[index--] = A[aIndex--];
}else
A[index--] = B[bIndex--];
}
//如果aIndex>=0,A中元素不需要处理
while(bIndex >= 0)
A[index--] = B[bIndex--];
}
}