归并排序的C语言实现【严蔚敏+算法导论】

#include<stdio.h>
void Merge(int *array_ptr,int start,int mid,int end);
void Merge_Sort(int *pointer,int start,int end );
#define N 2
#define M 88888
void main()
{
int array
;
int i=0;
for(i=0;i<N;i++)
{
array[i]=rand()%N;
printf("%d\t",array[i]);
}
Merge_Sort(array,0,N-1);
printf("\n");
for(i=0;i<N;i++)
{
printf("%d\t",array[i]);
}
}
Merge_Sort(int *pointer,int start,int end )
{
int middle=0;
if(start<end)
{
middle=(start+end)/2;
Merge_Sort(pointer,start,middle);
Merge_Sort(pointer,middle+1,end);
Merge(pointer,start,middle,end);
}
}
Merge(int *array_ptr,int start,int mid,int end)
{
int length1=mid-start+1;
int length2=end-mid;
int *leftbuff=NULL;
int *Rightbuff=NULL;
int i=0;
int j=0;
int k=0;
leftbuff=(int*)malloc(sizeof(int)*length1);
Rightbuff=(int*)malloc(sizeof(int)*length2);
for(i=0;i<length1;i++)
{
leftbuff[i]=array_ptr[start+i];
}
for(j=0;j<length2;j++)
{
Rightbuff[j]=array_ptr[mid+j+1];
}
leftbuff[length1]=M;
Rightbuff[length2]=M;
i=0;
j=0;
for(k=start;k<=end;k++)
{
if(leftbuff[i]<=Rightbuff[j])
{
array_ptr[k]=leftbuff[i];
i++;
}
else
{
array_ptr[k]=Rightbuff[j];
j++;
}
}
free(leftbuff);
free(Rightbuff);

}

#define MERGE_SORT
#ifdef MERGE_SORT

#define LQ(a,b) (a<=b)
//typedef int (*PARR)[6];
//int tr2[6] = {0};
void merge(int sr[],int tr[],int i,int m,int n)
{
int k = 0,j = 0;
for(j = m + 1,k = i;i<=m&&j<=n;++k)
{
if(LQ(sr[i],sr[j]))
tr[k] = sr[i++];
else
tr[k] = sr[j++];
}
/*while(i<=m)
tr[k++] = sr[i++];
while(j<=n)
tr[k++] = sr[j++];*/
if(i<=m)
memmove(tr+k,sr+i,m-i+1);
if(j<=n)
memmove(tr+k,sr+j,n-j+1);
}
void msort(int sr[],int tr[],int s,int t)
{
//int* tr2 = (int*)malloc(6*sizeof(int));
int tr2[6] = {0};
int m = 0;
if(s==t)
tr[s] = sr[s];
//return;
else
{
m = (s+t)/2;
msort(sr,tr2,s,m);
msort(sr,tr2,m+1,t);
merge(tr2,tr,s,m,t);
}
}

int main()
{
int i = 0;

int arr[6] = {7,1,3,9,4,5};
//int arr[3] = {7,1,3};
int *ptmpArr = (int*)malloc(6*sizeof(int));
//int tmpArr[6] = {0};
memset(ptmpArr,0,6*sizeof(int));
msort(arr,ptmpArr,0,5);
/*msort(arr,arr,0,5);这样传参数也是OK的*/
for(int i = 0;i<6;i++)
{
printf("%2d ",ptmpArr[i]);
}
free(ptmpArr);
getchar();
return 0;
}
#endif