第三周作业——冒泡排序和归并排序（计科1113练思安）

代码：

import java.io.*;

public class t02

{
public static void partition(String [] arr,int from,int end)
{
if(from<end)
{
int mid=(from+end)/2;
partition(arr,from,mid);
partition(arr,mid+1,end);
merge(arr,from,end,mid);
}

}
public static void merge(String [] arr,int from,int end,int mid)
{
String [] tmpArr=new String[end];
int tmpArrIndex=0;
int part1ArrIndex=from;
int part2ArrIndex=mid+1;
int l;
while((part1ArrIndex<=mid)&&(part2ArrIndex<=end))
{
l=arr[part1ArrIndex.compareTo(arr[part2ArrIndex])]
if(l<0)
{
tmpArr[tmpArrIndex++]=arr[part1ArrIndex++];
}
else
{
tmpArr[tmpArrIndex++]=arr[part2ArrIndex++];
}
}
while(part1ArrIndex<mid)
{
tmpArr[tmpArrIndex++]=arr[part1ArrIndex++];

}
while(part2ArrIndex<end-1)
{
tmpArr[tmpArrIndex++]=arr[part2ArrIndex++];
}
}
public static void main(String [] args)
throw Exception
{
try
{
FileReader fr=new FileReader("F:\\largeW.txt");
BufferdReader br=new BufferedReader(fr);
int len=0;
while(br.readLine()!null)
{
len++;
}
System.out.println(len);
String [] s=new String[len];
int t=0;
String r1="";
FileReader fr1=new FileReader("F:\\largeW.txt");
BufferedReader br1=new BuffereReader(fr1);
while((r1=br1.readLine())!=null)
{
s[t]=r1;
t++;
}
System.out.println("文本数据量是："+len);
System.out.println("选取排序的文本数量为：20000");
len=20000;
int res;
String a;
long startTime=System.currentTimeMillis();
for(int i=0;i<len-1;i++)
for(int j=j+1;j<len;j++)
{
res=s[i].compareTo(s[j]);
if(res>0)
{
a=s[i];
s[i]=s[j];
s[j]=a;
}
}
long endTime=System.currentTimeMillis();
System.out.println("程序运行时间："+(endTime-startTime)+"ms");
FileWriter fw1=new FileWriter("F:\\largeW_merge.txt",true);
BufferedWriter writer1=new BufferedWriter(fw1);
for(int i=0;i<len;i++)    
{    

                writer1.write(s[i]+"\r\n");    

                  }    

                 }catch(IOException e)    

         {    

             System.out.println("ERROR");    

         }    

}

}
}

运行结果：