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插入排序算法&二路归并排序算法java实现

2012-04-17 19:56 134 查看
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package sortalgos;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 *
 * @author hitachi
 */
//实现插入排序算法
class insertSort{       
    public static void Sort(ArrayList<Double> myArr){
        if(myArr.size()==1||myArr==null)
            return;
        else{
            int i,j;
            for(j=1;j<myArr.size();j++){
                Double temp=myArr.get(j);
                i=j-1;
                while(temp.compareTo(myArr.get(i))<0){
                        myArr.set(i+1, myArr.get(i));
                        --i;
                        if(i<0)
                            break;
                }
                myArr.set(i+1, temp);
            }
        }
    }
}
class mergeSort{
    public static void merge(ArrayList<Double> sub0, ArrayList<Double> sub1, ArrayList<Double> dest){
        int i,j,k;
        if(sub0.size()+sub1.size()!=dest.size()){
            System.out.println("Size doesn't match");
            return;
        }
        i=0;
        j=0;
        k=0;
        while(true){
           if(i<sub0.size()&&j<sub1.size()){  //两边都还有值的情况
               if(sub0.get(i).compareTo(sub1.get(j))<0){
                  dest.set(k, sub0.get(i));
                  i++;
                  k++;
               }
               else{
                   dest.set(k, sub1.get(j));
                   j++;
                   k++;
               }
           }
           else if(i>=sub0.size()&&j<sub1.size()){  //仅单边有值情况1
               dest.set(k, sub1.get(j));
               j++;
               k++;
           }
           else if(i<sub0.size()&&j>=sub1.size()){  //仅单边有值情况2
               dest.set(k, sub0.get(i));
               i++;
               k++;
           }
           else
               break;
        }
    }
    public static void sort(ArrayList<Double> myArr){
        if(myArr.size()==1)
            return;
        else{
            List sub0=myArr.subList(0, myArr.size()/2);
            List sub1=myArr.subList(myArr.size()/2, myArr.size());
            ArrayList<Double> subAL0=new ArrayList<Double>(sub0);
            ArrayList<Double> subAL1=new ArrayList<Double>(sub1);
            sort(subAL0);
            sort(subAL1);
            merge(subAL0,subAL1,myArr);
        }
    }
}
class arrayPrinter{
    public static void print(ArrayList myArr){
        for(Object single : myArr){
//            System.out.println("The array by order now is:");
            System.out.print(single);
            System.out.print("  ");
        }
            System.out.println("  ");
    }
}

public class SortAlgos {

 
    /**
     * @param args the command line arguments
     */
    private static ArrayList<Double> myArr = new ArrayList<Double>();
    public static void main(String[] args) throws IOException {
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        while(true){
        myArr.clear();
        System.out.println("Enter some double values one by one,end with a '.' or empty line:");
        String readin=input.readLine();
        while(!"".equals(readin) &&!".".equals(readin)){
            Double tempD=new Double(readin);
            myArr.add(tempD);
            readin=input.readLine();
        }
        System.out.println("Your input order is:");
        arrayPrinter.print(myArr);
        
//**************************************************   要用哪种排序算法自己取消注释,并注释掉其他选项     
//        insertSort.Sort(myArr);              //插入排序
        mergeSort.sort(myArr);                  //二路归并排序
//**************************************************        
        
        System.out.println("After sorting, the order is:");
        arrayPrinter.print(myArr);
        System.out.println("Would you like another round?(Y/N)");
        readin=input.readLine();
        if(!("Y".equals(readin)||"y".equals(readin)))
            break;
        }        
     }
    
}
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