merge sort 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.

考虑从后往前比较，这样就不会产生需要数据后移的问题了。时间复杂度O(n+m)

class Solution {public:    void merge(int A[], int m, int B[], int n) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        int index = m + n - 1;        int aIndex = m - 1;        int bIndex = n - 1;        while(0 <= aIndex && 0 <= bIndex)        {            if (B[bIndex] > A[aIndex])            {                A[index--] = B[bIndex--];            }            else            {                A[index--] = A[aIndex--];            }        }                while(0 <= aIndex)        {            A[index--] = A[aIndex--];        }                while(0 <= bIndex)        {            A[index--] = B[bIndex--];        }    }};