LeetCode算法题解（6）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.
A和B都已经是排好序的数组，我们只需要从后往前比较就可以了。因为A有足够的空间容纳A + B，我们使用游标i指向m + n - 1，也就是最大数值存放的地方，从后往前遍历A，B，谁大就放到i这里，同时递减i。
代码如下：

#include<iostream>
using namespace std;

//返回合并后数组的指针
int *merge(int a[],int m,int b[],int n)
{
    int i=m+n-1;
    int j=m-1;
    int k=n-1;
    while (i>=0)
    {
        if (j>=0&&k>=0)
        {
            if (a[j]>b[k])
            {
                a[i]=a[j];
                j--;
            }
            else
            {
                a[i]=b[k];
                k--;
            }
        }
        else if (j>=0)
        {
            a[i]=a[j];
            j--;
        }
        else
        {
            a[i]=b[k];
            k--;
        }
        i--;
    }
    return a;
}

void main()
{
    int m=5,n=6;
    int a[11]={1,3,5,7,9};
    int b[6]={2,4,6,8,10,12};
    int* c=merge(a,m,b,n);
    cout<<"合并后的数组为：";
    for (int i=0;i<m+n;i++)
    {
        cout<<c[i]<<" ";
    }
    system("pause");
}