排序（快速排序）

教材：严版数据结构

页码：P272-276

实现：算法10.6-10.8

代码如下：

#include<stdio.h>
#include<iostream>
 
using namespace std;
#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define MAXSIZE 20
#define LT(a,b) (a<b)
#define EQ(a,b) (a==b)
 
typedef int Status;
typedef int KeyType;
typedef int InfoType;
typedef struct {
	KeyType key;//关键字项
	InfoType otherinfo;//其他数据项
}RedType;
 
typedef struct {
	RedType r[MAXSIZE + 1];//r[0]闲置或用作哨兵单位
	int length;//顺序表长度
}SqList;//顺序表类型
 
Status InitList(SqList &L)
{
	//构造一个空的顺序表L
	L.length = 0;//空表长度为0
	return OK;
}
//创建n个元素的顺序表
Status CreateList(SqList &L, int n)
{
	int i;
	cout << "输入" << n << "个元素" << endl;
	for (i = 1; i <= n; i++)
	{
		cin >> L.r[i].key;
		++L.length;
	}
	if (L.length == 0)
		return ERROR;//创建失败
	return OK;
}
//输出顺序表
Status DispList(SqList &L)
{
	int i;
	if (L.length == 0)
		return ERROR;
	for (i = 1; i <= L.length; i++)
	{
		cout << L.r[i].key << " ";
	}
	cout << endl;
	return OK;
}
//找到位置
int Partition(SqList &L, int low, int high)
{
	L.r[0] = L.r[low];
	int pivotkey = L.r[low].key;
	while (low < high)
	{
		while (low < high&&L.r[high].key >= pivotkey)
			--high;
		L.r[low] = L.r[high];
		while (low < high&&L.r[low].key <= pivotkey)
			++low;
		L.r[high] = L.r[low];
	}
	L.r[low] = L.r[0];
	return low;
}
//递归排序
void QSort(SqList &L, int low, int high)
{
	if (low < high)
	{
		
		int pivotloc = Partition(L, low, high);
		QSort(L, low, pivotloc - 1);//对底子表递归排序
		QSort(L, pivotloc + 1, high);//对高子表递归排序
	}
}
 
void QuickSort(SqList &L)
{
	QSort(L, 1, L.length);
}
 
 
void main()
{
	SqList L;
	int n;
	cout << "初始化顺序表，";
	InitList(L);
	if (L.length == 0)
		cout << "顺序表为空！\n";
	cout << "输入顺序表的元素个数:";
	cin >> n;
	CreateList(L, n);
	cout << "输出" << n << "个元素的顺序表如下:" << endl;
	DispList(L);
	QuickSort(L);
	cout << "快速排序结果如下：" << endl;
	DispList(L);
	system("pause");
}