第三周作业——冒泡排序和归并排序

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.List;

public class bubble {

public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
int t=0, flag = 10000;
String line = null;
List<Integer> list = new ArrayList<Integer>();
BufferedReader bReader = new BufferedReader(new FileReader("largeW.txt"));
while((line=bReader.readLine())!=null && t<flag){
list.add(new Integer(line.trim()));
t++;
}
bReader.close();
Integer[] data1 = new Integer[list.size()];
list.toArray(data1);

long start = System.currentTimeMillis();//获取开始时间
bubbleSort(data1);
long end = System.currentTimeMillis();//结束时间
System.out.println("冒泡排序的运行时间为："+(end-start)+"ms");

Integer[] data2 = new Integer[list.size()];
list.toArray(data2);
Integer[] d = new Integer[data2.length];

long b = System.currentTimeMillis();//获取开始时间
mergeSort(data2, d, 0, data2.length-1);
long e = System.currentTimeMillis();//结束时间
System.out.print("归并排序的运行时间为："+(e-b)+"ms");

FileWriter fw1 = new FileWriter(new File("merge.txt"));
for(int i=0; i<d.length; i++){
fw1.write(d[i]+"\n");
}
fw1.close();
FileWriter fw2 = new FileWriter(new File("bubble.txt"));
for(int i=0; i<data1.length; i++){
fw2.write(data1[i]+"\n");
}
fw2.close();
}
public static Integer[] bubbleSort(Integer a[]){//冒泡排序
int temp;
for(int j=0; j<a.length; j++){
for(int i=0; i<a.length-j-1; i++){
if(a[i] > a[i+1]){
temp = a[i];
a[i] = a[i+1];
a[i+1] = temp;
}
}
}
return a;
}
public static Integer[] mergeSort(Integer[] num, Integer[] num1, int s, int t) {//归并排序的递归算法

int m;
Integer[] num2 = new Integer[t + 1];
if (s == t)
num1[s] = num[s];     //待排序记录只有一个，递归结束

else {
m = (s + t) / 2;
mergeSort(num, num2, s, m);//左半部分递归调用
mergeSort(num, num2, m + 1, t);//右半部分递归调用
merg(num2, num1, s, m, t);//将两个已排序的子序列归并

}
return num1;
}

public static void merg(Integer[] num, Integer[] num1, int l, int m, int n) {//一次归并算法

int i, j, k;
i = l;
j = m + 1;
k = l;
while (i <= m && j <= n) {
if (num[i] < num[j])
num1[k++] = num[i++];
else {
num1[k++] = num[j++];
}
}

while (i <= m) {
num1[k++] = num[i++];
}
while (j <= n) {
num1[k++] = num[j++];
}

}

}