冒泡和歸并

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();//擷取開始時間

bubbleSort(data1);

long end = System.currentTimeMillis();//結束時間

System.out.println("冒泡排序的運作時間為："+(end-start)+"ms");

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

list.toArray(data2);

Integer[] d = new Integer[data2.length];

long b = System.currentTimeMillis();//擷取開始時間

mergeSort(data2, d, 0, data2.length-1);

long e = System.currentTimeMillis();//結束時間

System.out.print("歸并排序的運作時間為："+(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) {//歸并排序的遞歸算法

 int m;

 Integer[] num2 = new Integer[t + 1];

 if (s == t)

  num1[s] = num[s];     //待排序記錄隻有一個，遞歸結束

 else {

  m = (s + t) / 2;

  mergeSort(num, num2, s, m);//左半部分遞歸調用

  mergeSort(num, num2, m + 1, t);//右半部分遞歸調用

  merg(num2, num1, s, m, t);//将兩個已排序的子序列歸并

 }

 return num1;

}

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

 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++];

 }

}

}

選取largeW.txt檔案中的前10000條資料進行排序。。

運作結果：