[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.

給定兩個有序數組A和B，將B中的元素插入A（假設A有足夠大的空間），保持有序性

Tip: A和B的大小已知，即合併完成後的數組大小肯定。

將指針指向A和B的尾端，從數組的尾端(最大值)處開始合併。若B中仍有剩餘元素，所有插入A的頭部。

代碼

 1 class Solution {
 2 public:
 3     void merge(int A[], int m, int B[], int n) {
 4         // Note: The Solution object is instantiated only once and is reused by each test case.
 5         if(B==NULL || n==0)
 6             return;
 7         
 8         int p=m-1, q=n-1, cur=m+n-1;
 9         while(p>=0 && q>=0)
10         {
11             if(A[p]>=B[q])
12             {
13                 A[cur--] = A[p--];
14             }
15             else
16             {
17                 A[cur--] = B[q--];
18             }
19         }
20         while(q>=0)
21             A[cur--] = B[q--];
22     }
23 };