【leetcode】Merge Sorted Array

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 mand n respectively

这道题目就是从后向前进行比较，然后替换。
特别注意比较外的循环条件，当且仅当有一个数组为0的时候就得退出。后面两个while是把剩余的数据填进去。

class Solution {public:    void merge(int A[], int m, int B[], int n) {        int num=m+n-1;        int recordA=m-1;        int recordB=n-1;        while(recordA>=0 && recordB>=0)        {            if(B[recordB]>=A[recordA])            {                A[num]=B[recordB];                recordB--;            }            else            {                A[num]=A[recordA];                recordA--;            }            num--;        }        while(recordA>=0)        {            A[num]=A[recordA];            recordA--;            num--;        }        while(recordB>=0)        {            A[num]=B[recordB];            recordB--;            num--;        }    }};