实验8排序算法实验比较
背景
排序是计算机内经常进行的一种操作，其目的是将一组“无序”的记录序列调整为“有序”的记录序列。
假设含n个记录的序列为{ R1, R2, …， Rn }
其相应的关键字序列为 { K1, K2, …，Kn }
这些关键字相互之间可以进行比较，即在它们之间存在着这样一个关系 ：
Kp1≤Kp2≤…≤Kpn
按此固有关系将上式记录序列重新排列为{ Rp1, Rp2, …，Rpn }的操作称作排序。
排序算法是计算机科学中最重要的研究问题之一。对于排序的研究既有理论上的重要意义，又有实际应用价值。它在计算机图形、计算机辅助设计、机器人、模式识别、及统计学等领域具有广泛应用。 常见的排序算法有起泡排序、直接插入排序、简单选择排序、快速排序、堆排序等。
例1：有时候应用程序本身就需要对信息进行排序。为了准备客户账目，银行需要根据支票的号码对支票排序；
例2：在一个绘制互相重叠的图形对象的程序中，可能需要根据一个“在上方”关系将各对象排序，以便自下而上地绘出对象。
例3：在一个由n个数构成的集合上，求集合中第i小/大的数。
例4：对一个含有n个元数的集合，求解中位数、k分位数。
实验目的
基于教材内容，任选两种排序算法，实现并比较性能。
基本要求
（1）至少要有一种排序算法的性能优于O(n2)
（2）对实现的排序算法进行实验比较，实验比较数据参见教材7.8章节
（3）排序算法要基于教材，测试输入的整数数据文件（5个，文件中数据规模分别是100，1K，10K，100K和1M），排序结果也要输出到文件中。
（4）要在屏幕上输出排序过程所花费时间
代码实现
#include<iostream>
#include<fstream>
#include<windows.h>
using namespace std;
LARGE_INTEGER frequency;
int A[1000001],temp[1000001];
int count=0;
void Init(ifstream &infile)
{
int a;
while(!infile.eof())
{
infile>>a;
A[count]=a;
count++;
}
}
void print(ofstream &outfile)
{
for(int i=0;i<count;i++)
{
outfile<<A[i]<<' ';
}
}
int partition(int A[],int l,int r,int p)
{
do
{
while(A[++l]<p);
while(l<r&&A[--r]>p);
swap(A[l],A[r]);
}
while(l<r);
return l;
}
void qsort(int A[],int i,int j)
{
if(j<=i)
return;
int p=(i+j)/2;
swap(A[p],A[j]);
int k=partition(A,i-1,j,A[j]);
swap(A[k],A[j]);
qsort(A,i,k-1);
qsort(A,k+1,j);
}
bool cmp(int x,int y)
{
return x<y;
}
void mergesort(int A[],int temp[],int left,int right)
{
if(left==right)
return;
int mid=(left+right)/2;
mergesort(A,temp,left,mid);
mergesort(A,temp,mid+1,right);
for(int i=left;i<=right;i++)
temp[i]=A[i];
int i1=left;
int i2=mid+1;
for(int curr=left;curr<=right;curr++)
{
if(i1==mid+1)
A[curr]=temp[i2++];
else if(i2>right)
A[curr]=temp[i1++];
else if(cmp(temp[i1],temp[i2]))
A[curr]=temp[i1++];
else
A[curr]=temp[i2++];
}
}
int main()
{
ifstream test_100("100.txt");
ifstream test_1K("1K.txt");
ifstream test_10K("10K.txt");
ifstream test_100K("100K.txt");
ifstream test_1M("1M.txt");
ofstream output_100("output_100.txt");
ofstream output_1K("output_1K.txt");
ofstream output_10K("output_10K.txt");
ofstream output_100K("output_100K.txt");
ofstream output_1M("output_1M.txt");
double dff,begin,end,dfm,dft;
Init(test_100);
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
qsort(A,0,100);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
print(output_100);
cout<< "快速排序100："<<dft*1000<<"ms"<<endl;
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
mergesort(A,temp,0,100);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
cout<<"归并排序100："<<dft*1000<<"ms"<<endl;
Init(test_1K);
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
qsort(A,0,1000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
print(output_1K);
cout<<"快速排序1K："<<dft*1000<<"ms"<<endl;
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
mergesort(A,temp,0,1000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
cout<<"归并排序1K："<<dft*1000<<"ms"<<endl;
Init(test_10K);
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
qsort(A,0,10000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
print(output_10K);
cout<<"快速排序10K："<<dft*1000<<"ms"<<endl;
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
mergesort(A,temp,0,10000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
cout<<"归并排序10K："<<dft*1000<<"ms"<<endl;
Init(test_100K);
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
qsort(A,0,100000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
print(output_100K);
cout<<"快速排序100K："<<dft*1000<<"ms"<<endl;
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
mergesort(A,temp,0,100000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
cout<<"归并排序100K："<<dft*1000<<"ms"<<endl;
Init(test_1M);
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
qsort(A,0,1000000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
print(output_1M);
cout<<"快速排序1M："<<dft*1000<<"ms"<<endl;
QueryPerformanceFrequency(&frequency);//获得时钟频率
dff=(double)frequency.QuadPart;
QueryPerformanceCounter(&frequency);//获得初始值
begin=frequency.QuadPart;
mergesort(A,temp,0,1000000);
QueryPerformanceCounter(&frequency);//获得终止值
end=frequency.QuadPart;
dfm=(double)(end-begin);
dft=dfm/dff;
cout<<"归并排序1M："<<dft*1000<<"ms"<<endl;
return 0;
}
完整代码及输入输出样例：https://github.com/Prince9821/Data-stucture