88、Merge Sorted Array

题目：

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1 and nums2 are m and n respectively.
解题思路：
典型的归并排序。但由于存在如下输入：

Input: [1,0] 1

[2] 1

不可以用一般的从前向后的归并法，因为对于多于的元素无从安置，需要从后向前进行归并方可。

python 版本：

class Solution(object):
def merge(self, nums1, m, nums2, n):
"""
:type nums1: List[int]
:type m: int
:type nums2: List[int]
:type n: int
:rtype: void Do not return anything, modify nums1 in-place instead.
"""
index = m+n-1
i,j = m-1,n-1
while(i>=0 and j>=0):
if(nums1[i]>=nums2[j]):
nums1[index] = nums1[i]
index -= 1
i -= 1
else:
nums1[index] = nums2[j]
index -= 1
j -= 1
if(i==-1):
while(j>=0):
nums1[j] = nums2[j]
j -= 1