[LeetCode]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 to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

给定两个有序数组A和B，将B中的元素插入A（假设A有足够大的空间），保持有序性

Tip: A和B的大小已知，即合并完成后的数组大小确定。

将指针指向A和B的尾端，从数组的尾端(最大值)处开始合并。若B中仍有剩余元素，全部插入A的头部。

代码

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(B==NULL || n==0)
            return;
        
        int p=m-1, q=n-1, cur=m+n-1;
        while(p>=0 && q>=0)
        {
            if(A[p]>=B[q])
            {
                A[cur--] = A[p--];
            }
            else
            {
                A[cur--] = B[q--];
            }
        }
        while(q>=0)
            A[cur--] = B[q--];
    }
};