归并排序

//MergeSort.h

#ifndef _MERGESORT_H_
#define _MERGESORT_H_

#include <stdlib.h>
#include <stdio.h>
#include <memory.h>
#include <time.h>

#define SIZE	15

typedef int Element;
typedef Element ListType[SIZE];

void CreateRandom(ListType List, int n);
void print(ListType List, int n);

//归并排序
void MergeSort(ListType List, int n);


#endif //_MERGESORT_H_

//MergeSort.c

#include "MergeSort.h"

void CreateRandom(ListType List, int n)
{
	int i = 0;
	srand((unsigned)time(NULL));

	for (i = 0; i < n; ++i)
	{
		List[i] = rand() % 0x7F;
	}
}

void print(ListType List, int n)
{
	int i = 0;
	for (i = 0; i < n; ++i)
	{
		printf("%d\t", List[i]);
	}
	printf("\n");
}

/***********************************************************
归并排序是利用分治思想，对一个无序序列进行不停的分割，直至分割成
n个子序列，再对每个子序列进行排序，排序完成后将所有有序子序列归并
成一个有序序列，排序完成
***********************************************************/
static void Merge(ListType List, ListType Tp, int Left, int Right)
{
	int i = 0, Mid = 0, s1 = 0, s2 = 0;
	for(i = Left; i <= Right; ++i)						//将子数组的值赋值到辅助空间
	{
		Tp[i] = List[i];
	}

	Mid = (Left + Right) / 2;							//找到辅助空间中元素的中间位置，将元素分为两份
	s1 = Left;
	s2 = Mid + 1;

	while (s1 <= Mid && s2 <= Right)					//比较辅助空间中的两份子数组，将较小的值放回
	{
		if( Tp[s1] >= Tp[s2] )
		{
			List[Left++] = Tp[s2++];
		}
		else
			List[Left++] = Tp[s1++];
	}

	//放回剩余元素
	while (s1 <= Mid)
		List[Left++] = Tp[s1++];

	while (s2 <= Right)
		List[Left++] = Tp[s2++];
}

//分解无序数组
static void Resolve(ListType List, ListType Tp, int Left, int Right)
{
	int Mid = 0;

	if( Left >= Right )
		return ;
	Mid = (Left + Right) / 2;
	Resolve(List, Tp, Left, Mid);
	Resolve(List, Tp, Mid + 1, Right);
	Merge(List, Tp, Left, Right);
}


void MergeSort(ListType List, int n)
{
	ListType Tp;						//辅助空间
	memset(Tp, 0, sizeof(Tp));

	Resolve(List, Tp, 0, n-1);
}

//main.c

#include "MergeSort.h"

int main(int argc, char **argv)
{
	ListType List ={ 0 };
	int n = sizeof(List) / sizeof(Element);

	CreateRandom(List, n);
	printf("排序前\n");
	print(List, n);

	MergeSort(List, n);

	printf("排序后\n");
	print(List, n);

	system("pause");
	return 0;
}