Leetcode: Merge Sorted Array

题目：

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.

思路分析：

我刚开始是从前面开始比较的，发现要移动很多元素，后来从后面进行比较，代码异常简单！

C++参考代码：

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;
//两个数组同时从后面进行比较，将大的放在A数组末尾
while (i >= 0 && j >= 0)
{
A[k--] = A[i] > B[j] ? A[i--] : B[j--];
}
//如果经过上面的while循环比较后B数组还有元素，则这些元素都小于A中最小元素，直接放入A数组最前面就好
while (j >= 0)
{
A[k--] = B[j--];
}
}
};