南郵《算法設計與分析》第一次實驗源碼

合併排序和快排及改進快排

template<class T>
class SortableList
{
public:
	SortableList(int mSize)
	{
		maxSize=mSize;
		l=new T[maxSize];
		n=0;
	}

	~SortableList()
	{
		delete []l;
	}

	void Input();//輸入
	void Output();
	void MergeSort();//合併排序
	void QuickSort();//快排
private:
	int maxSize;
	int n;
	T *l;

	void MergeSort(int left,int right);//合併排序
	void Merge(int left,int mid,int right);//將兩個有序序列合併成一個有序序列，時間複雜度爲O(n)
	void Swap(int i,int j);
	void QuickSort(int left,int right);
	int Partition(int left,int right);
	int RandomPartition(int left,int right);

};
template<class T>
void SortableList<T>::Input()
{
	int m;

	cout<<"輸入這個序列的個數"<<endl;
	cin>>m;
	n=m;
	T *ll=new T[n];
	cout<<"輸入序列"<<endl;
	for(int i=0;i<n;i++)
	{
 		cin>>ll[i];
		l[i]=ll[i];
	}
	


}
template<class T>
void SortableList<T>::Output()
{
	cout<<"排序的結果是"<<endl;
	for(int i=0;i<n;i++)
	{
		cout<<l[i]<<"  ";
	}
	cout<<endl;
}

template<class T>
void SortableList<T>::Swap(int i,int j)
{
	T temp;
	temp=l[i];
	l[i]=l[j];
	l[j]=temp;
}

template<class T>
void SortableList<T>::MergeSort()
{
	MergeSort(0,n-1);
}

template<class T>
void SortableList<T>::MergeSort(int left,int right)
{
	if(left<right)
	{
		int mid=(left+right)/2;
		MergeSort(left,mid);
		MergeSort(mid+1,right);
		Merge(left,mid,right);
	}
}

template<class T>
void SortableList<T>::Merge(int left,int mid,int right)
{
	T* temp=new T[right-left+1];
	int i=left,j=mid+1,k=0;
	while((i<=mid)&&(j<=right)){
		if(l[i]<=l[j]) temp[k++]=l[i++];
		else temp[k++]=l[j++];
	}

	while(i<=mid)
	{
		temp[k++]=l[i++];
	//	cout<<temp[k-1];
	}
	while(j<=right)
		temp[k++]=l[j++];
	for(i=0,k=left;k<=right; ) l[k++]=temp[i++];

	delete []temp;	
}


template<class T>
void SortableList<T>::QuickSort()
{
	QuickSort(0,n-1);
}

template<class T>
void SortableList<T>::QuickSort(int left,int right)
{
	if(left<right)
	{
		int j=Partition(left,right);
		//int j=RandomPartition(left,right);
		QuickSort(left,j-1);
		QuickSort(j+1,right);
	}
}

template<class T>
int SortableList::RandomPartition(int left,int right)
{
	srand((unsigned)time(NULL));
	int i=rand()%(right-left)+left;
	Swap(i,left);
	return Partition(left,right);
}
template<class T>
int SortableList<T>::Partition(int left,int right)
{
	int i=left,j=right+1;
	do{
		do i++; while(l[i]<l[left]);
		do j--; while(l[j]>l[left]);
		
		if(i<j) 
		{
			Swap(i,j);
		}
		
	}while(i<j);
	Swap(left,j);
	
	return j;
}
測試函數
#include<iostream>

using namespace std;
#include"sortedable.h"


int main()
{
	SortableList<int> *s=new SortableList<int>(50);
	char c;
menu:cout<<"**************1,合併排序************"<<endl;
	cout<<"**************2,快速排序************"<<endl;
	cout<<"**************0,退出    ************"<<endl;
	cin>>c;
	switch(c)
	{
	case '1':
		s->Input();
		s->MergeSort();
		s->Output();
		goto menu;
		break;
	case '2':
		s->Input();
		s->QuickSort();
		s->Output();
		goto menu;
		break;
	case '0':
		
		break;
	default:
		cout<<"輸入錯誤"<<endl;
		goto menu;
		break;
	}
	return 0;
}