Algs4-2.1.36不均匀的数据
2.1.36不均匀的数据。编写一个测试用例,生成不均匀的测试数据,包括:
1)一半数据是0,一半是1;
2)一半数据是0,1/4是1,1/4是2,以此类推;
3)一半数据是0,一半是随机int值。
评估并验证这些输入数据对本节讨论的算法的性能的影响。
1)打乱次序后的结果:
一百万个数10次运行的平均时间。选择排序性能最差。希尔排序性能最好。
![图片](http://r.photo.store.qq.com/psb?/f33bb27a-608a-4097-811a-86bbde18cf7a/57Ugj9FwujbzRxgTevV5E*LNPvTXTb6TMkxZ2SKVGjk!/o/dB8BAAAAAAAA&ek=1&kp=1&pt=0&bo=AwLeAAMC3gADEDU!&tl=1&su=0239747377&tm=1540602000&sce=0-12-12&rf=2-9)
2)未打乱次序后的结果:
一百万个数10次运行的平均时间。选择排序性能最差。希尔排序整体性能最好,对于数据情况1,2
时希尔排序的性能比插入排序优势不明显。
![图片](http://r.photo.store.qq.com/psb?/f33bb27a-608a-4097-811a-86bbde18cf7a/WU3Z9DMw0QixtNI*wzhWyZa*uNbGsiDiwLeuh3REuWc!/o/dCABAAAAAAAA&ek=1&kp=1&pt=0&bo=.wHcAPsB3AADEDU!&tl=1&su=032180865&tm=1540602000&sce=0-12-12&rf=2-9)
以下是未打乱的代码,打乱的代码只需去掉打代码的注释即可。
public class E2d1d36
{
public static double time (String alg,Integer[] a)
{
Stopwatch timer =new Stopwatch();
if(alg.equals("Insertion")) Insertion.sort(a);
if(alg.equals("Selection")) Selection.sort(a);
if(alg.equals("Shell")) Shell.sort(a);
// if(alg.equals("Merge")) Merge.sort(a);
// if(alg.equals("Quick")) Quick.sort(a);
// if(alg.equals("Heap")) Heap.sort(a);
return timer.elapsedTime();
}
public static double timeRandomInput(String alg,int N,int T,int probabilityTYPE)
{
double total =0.0;
Integer[] a=new Integer[N];
if (probabilityTYPE==0)
{
for (int t=0;t<T;t++)
{
generateHalf0Half1(a);
total+=time(alg,a);
}
}
//probabilityTYPE=1 Poisson distribution
if (probabilityTYPE==1)
{
for (int t=0;t<T;t++)
{
generateHalf012(a);
total+=time(alg,a);
}
}
//probabilityTYPE=2 Geometric distribution
if (probabilityTYPE==2)
{
for (int t=0;t<T;t++)
{
generateHalf0HalfRandom(a);
total+=time(alg,a);
}
}
return total;
}//end timeRandomInput
public static void generateHalf0Half1(Integer[] a)
{
int half=a.length/2;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<a.length;i++)
a[i]=1;
//StdRandom.shuffle(a);
}
public static void generateHalf012(Integer[] a)
{
int half=a.length/2;
int over14=a.length/4;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<half+over14;i++)
a[i]=1;
for (int i=half+over14;i<a.length;i++)
a[i]=2;
//StdRandom.shuffle(a);
}
public static void generateHalf0HalfRandom(Integer[] a)
{
int half=a.length/2;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<a.length;i++)
a[i]=StdRandom.uniform(10*a.length);
//StdRandom.shuffle(a);
}
public static void main(String[] args)
{
Integer N=Integer.parseInt(args[0]);
Integer T=Integer.parseInt(args[1]);
String[] CASEmem=new String[4];
CASEmem[0]="1/2 0,1/2 1";
CASEmem[1]="1/2 0,1/4 1,1/4 2";
CASEmem[2]="1/2 0,1/2 random";
Double time;
StdOut.printf("---Insertion---\n");
time=timeRandomInput("Insertion",N,T,0);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Insertion",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Insertion",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
StdOut.printf("---Selection---\n");
time =timeRandomInput("Selection",N,T,0);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Selection",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Selection",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
StdOut.printf("---Shell---\n");
time =timeRandomInput("Shell",N,T,0);
StdOut.printf("For %d intuble with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Shell",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Shell",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
}
}
1)一半数据是0,一半是1;
2)一半数据是0,1/4是1,1/4是2,以此类推;
3)一半数据是0,一半是随机int值。
评估并验证这些输入数据对本节讨论的算法的性能的影响。
1)打乱次序后的结果:
一百万个数10次运行的平均时间。选择排序性能最差。希尔排序性能最好。
2)未打乱次序后的结果:
一百万个数10次运行的平均时间。选择排序性能最差。希尔排序整体性能最好,对于数据情况1,2
时希尔排序的性能比插入排序优势不明显。
以下是未打乱的代码,打乱的代码只需去掉打代码的注释即可。
public class E2d1d36
{
public static double time (String alg,Integer[] a)
{
Stopwatch timer =new Stopwatch();
if(alg.equals("Insertion")) Insertion.sort(a);
if(alg.equals("Selection")) Selection.sort(a);
if(alg.equals("Shell")) Shell.sort(a);
// if(alg.equals("Merge")) Merge.sort(a);
// if(alg.equals("Quick")) Quick.sort(a);
// if(alg.equals("Heap")) Heap.sort(a);
return timer.elapsedTime();
}
public static double timeRandomInput(String alg,int N,int T,int probabilityTYPE)
{
double total =0.0;
Integer[] a=new Integer[N];
if (probabilityTYPE==0)
{
for (int t=0;t<T;t++)
{
generateHalf0Half1(a);
total+=time(alg,a);
}
}
//probabilityTYPE=1 Poisson distribution
if (probabilityTYPE==1)
{
for (int t=0;t<T;t++)
{
generateHalf012(a);
total+=time(alg,a);
}
}
//probabilityTYPE=2 Geometric distribution
if (probabilityTYPE==2)
{
for (int t=0;t<T;t++)
{
generateHalf0HalfRandom(a);
total+=time(alg,a);
}
}
return total;
}//end timeRandomInput
public static void generateHalf0Half1(Integer[] a)
{
int half=a.length/2;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<a.length;i++)
a[i]=1;
//StdRandom.shuffle(a);
}
public static void generateHalf012(Integer[] a)
{
int half=a.length/2;
int over14=a.length/4;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<half+over14;i++)
a[i]=1;
for (int i=half+over14;i<a.length;i++)
a[i]=2;
//StdRandom.shuffle(a);
}
public static void generateHalf0HalfRandom(Integer[] a)
{
int half=a.length/2;
for (int i=0;i<half;i++)
a[i]=0;
for (int i=half;i<a.length;i++)
a[i]=StdRandom.uniform(10*a.length);
//StdRandom.shuffle(a);
}
public static void main(String[] args)
{
Integer N=Integer.parseInt(args[0]);
Integer T=Integer.parseInt(args[1]);
String[] CASEmem=new String[4];
CASEmem[0]="1/2 0,1/2 1";
CASEmem[1]="1/2 0,1/4 1,1/4 2";
CASEmem[2]="1/2 0,1/2 random";
Double time;
StdOut.printf("---Insertion---\n");
time=timeRandomInput("Insertion",N,T,0);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Insertion",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Insertion",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
StdOut.printf("---Selection---\n");
time =timeRandomInput("Selection",N,T,0);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Selection",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Selection",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
StdOut.printf("---Shell---\n");
time =timeRandomInput("Shell",N,T,0);
StdOut.printf("For %d intuble with case %s,spend time=%.2f\n",N,CASEmem[0],time);
time =timeRandomInput("Shell",N,T,1);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[1],time);
time =timeRandomInput("Shell",N,T,2);
StdOut.printf("For %d int with case %s,spend time=%.2f\n",N,CASEmem[2],time);
}
}