归并排序

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #define elementType int
 4 
 5 void mergeSort(elementType A[], int N);//N为数组大小，统一函数接口
 6 void mSort(elementType A[], elementType tmpA[], int L, int rightEnd);//传入左右边界
 7 void merge(elementType A[], elementType tmpA[], int L, int R, int rightEnd);//将有序的两个部分进行归并
 8 
 9 
10 int main()
11 {
12     int N;
13     scanf("%d", &N);
14     elementType* A = (elementType*)malloc(N * sizeof(elementType));
15     for (int i = 0; i < N; i++)
16         scanf("%d", &A[i]);
17     mergeSort(A, N);
18     for (int i = 0; i < N; i++)
19         printf("%d ", A[i]);
20     return 0;
21 }
22 
23 void mergeSort(elementType A[], int N) {
24     elementType* tmpA = (elementType*)malloc(N * sizeof(elementType));//申请内存建立临时数组
25     if (tmpA != NULL) {
26         mSort(A, tmpA, 0, N - 1);
27         free(tmpA);
28     }
29     else
30         printf("Error!\n");//内存申请失败
31 }
32 
33 void mSort(elementType A[], elementType tmpA[], int L, int rightEnd) {
34     if (L < rightEnd) {
35         int center = (L + rightEnd) / 2;
36         mSort(A, tmpA, L, center);
37         mSort(A, tmpA, center + 1, rightEnd);
38         merge(A, tmpA, L, center + 1, rightEnd);
39     }
40 }
41 
42 void merge(elementType A[], elementType tmpA[], int L, int R, int rightEnd) {
43     int tmpL = L,
44         leftEnd = R - 1,
45         elementNum = rightEnd - L + 1;
46     while (L <= leftEnd && R <= rightEnd) {
47         if (A[L] < A[R])
48             tmpA[tmpL++] = A[L++];
49         else 
50             tmpA[tmpL++] = A[R++];
51     }
52     while (L <= leftEnd)
53         tmpA[tmpL++] = A[L++];
54     while (R <= rightEnd)
55         tmpA[tmpL++] = A[R++];
56     for (int i = 0; i < elementNum; i++, rightEnd--)
57         A[rightEnd] = tmpA[rightEnd];
58 }