合並有序數組，合並數組

合並有序數組，合並數組

有兩個排序數組A1和A2，內存在A1的末尾有足夠多的空余空間容納A2，實現一個函數，把A2插入到A1，並且是有序的。 

分析:從尾到頭比較A1和A2的數字，並把較大的數字復制到合適的位置。

 1 #include <stdio.h>
 2 #include "stdafx.h"
 3 
 4 void DisplayArray(int* pArray, int nLength)
 5 {
 6     for(int i = 0 ; i < nLength; ++i)
 7         printf("%d\t", pArray[i]);
 8     printf("\n");
 9 }
10 
11 int *MergeArray(int* pArray1, int nLength1, int* pArray2, int nLength2, int* pArray3)
12 {
13     if(pArray1 == NULL || pArray2 == NULL)
14         return NULL;
15 
16     int k = nLength1 + nLength2 -1;
17     int i = nLength1 - 1;
18     int j = nLength2 - 1;
19     
20     //先將array1復制到array3前面 
21     for(int n = 0 ; n <= i; n ++)
22         pArray3[n] = pArray1[n];
23     
24     
25     //從後往前比較array1和array2 
26     while(i >= 0 && j >=0)
27     {
28         if(pArray1[i] > pArray2[j])
29             pArray3[k --] = pArray1[i --];
30         else
31             pArray3[k--] = pArray2[j--];
32     }
33     while(j >= 0)
34         pArray3[k --] = pArray2[j --];
35 
36     return pArray3;
37 }
38 
39 int main()
40 {
41     int array1[] = {1,4,5,7};
42     int length1 = sizeof(array1)/sizeof(int);
43     printf("array1 is: ");
44     DisplayArray(array1, length1);
45 
46     int array2[] = {2,3,6,8};
47     int length2 = sizeof(array2)/sizeof(int);
48     printf("array2 is: ");
49     DisplayArray(array2, length2);
50 
51     int length3= length1 + length2;
52     int array3[length3];
53 
54     int *pArray3 = MergeArray(array1,length1,array2,length2,array3);
55     printf("Merge Array: \n");
56     DisplayArray(pArray3, length3);
57 
58     return 0;
59 }