有一个Vector里面存放一组值,我想取出尽量三组不同的值,请熟悉的人给发方法,多谢

[dreamingdan]

下面是我写的方法,但感觉应该是不多,请高手指点一下,最后也能写出代码,谢谢:
public static String[] getElementFromVector(Vector vector){
int i = 0;
String str[] = null;
String strData[] = null;
str = new String[15];
strData = new String[3];

Enumeration e = vector.elements();
while(e.hasMoreElements()){
str[i] = (String)e.nextElement();
if(str[i].compareTo(str[i-1])>0){
strData[i] = str[i];
}
else
strData[i] = str[i-1];

i++;
}

return strData;
}

[sunnyfun888]

if(count <= 0){
break;
}
是多余的，可以去掉

[bigbug9002]

我可能考虑的太多了,我考虑了值相同但引用不同的字符串,尽量让结果中相同的字符串的引用不相同.

实际上字符串可以看成是常量,所以我的考虑是杞人忧天了。

[sunnyfun888]

[Quote=引用 16 楼 sunnyfun888 的回复:]
                if(count <= 0){
                    break;
                }
是多余的，可以去掉
[/Quote]

当不一样的字符串个数超过3个是还是需要的。

[zhouzongjiu]

public static List getElementFromVector(Vector vector) { 
        List strData =  new ArrayList(); 
        
        if (vector != null && vector.size() >=3) {
	        strData.add(vector.get(0));
	        for (int i = 1; i < vector.size(); i++) {
	        	if (!strData.contains(vector.get(i))) {
	        		strData.add(vector.get(i));
				}
	        	if (strData.size() >= 3) {
	        		break;
	        	}
	        }
	        
	        if (strData.size() == 1) {
	        	strData.add(strData.get(0));
	        	strData.add(strData.get(0));
	        }
	        if (strData.size() == 2) {
	        	if (strData.get(1).equals(vector.get(1))) {
	        		strData.add(vector.get(2));
				} else {
					strData.add(1,vector.get(1));
				}
	        }
        }
        return strData; 
    }

[bigbug9002]

三个还是三组?

[dreamingdan]

三个
比如里面的值是1,1,1,1,2,1,3,4,1那就从1234中取三个就行
1,1,1,1,1,1,3,4,1那就从134中取三个
1,1,1,1,1,1,1,4,1那就从114取三个
1,1,1,1,1,1,1,1,1那就从111中取三个
请朋友们写出实现代码,谢谢

[dreamingdan]

我修改了下,请帮我看看是否正确
public static String[] getElementFromVector(Vector vector) {
String strData[] = new String[3];
String a="";
int s=0;
Enumeration e = vector.elements();
while (e.hasMoreElements()) {
String vv = (String)e.nextElement();
if(a.indexOf(vv+",")<0){
a+=vv+",";
strData[s]=vv;
s++;
}
}
for (int i = 0; i < strData.length; i++) {
String s1 = strData[i];
if(s1==null)
{
strData[i]=strData[0];
}
}

return strData;
}

[bigbug9002]

import java.util.*;

public class Test4{
	public static void main(String[] args){
        Vector<String> myVector=new Vector<String>(Arrays.asList("1","1","2","3","2","4","3"));
        String[] result=getElementFromVector(myVector,3);
        System.out.println(Arrays.toString(result));

	}
	public static String[] getElementFromVector(Vector<String> vector,int count){ 
		Set<String> mySet=new HashSet<String>(vector);
		if(mySet.size()<count){
			System.out.println("不相同的元素数量不够");
		}
		String[] result=new String[count];
		int index=count-1;
		for(String str:mySet){
			if(index<0){
				break;
			}
			result[index--]=str;
		}
		return result;
	}
	
}

[bigbug9002]

可以相同啊????

[gukuitian]

尽量三组不同的值
有点模糊啊，到底能不能相同呢

[弘石]

不如先去掉相同的值，然后再取值

[dreamingdan]

bigbug9002谢谢你的热心帮忙啊,那么我上面的实现方法有问题吗?

[bigbug9002]

[Quote=引用 8 楼 qiangtien 的回复:]
bigbug9002谢谢你的热心帮忙啊,那么我上面的实现方法有问题吗?
[/Quote]
我看不懂你的代码,下面是我的代码,我估计你也看不懂我的代码.
好在我的代码能出来结果:

import java.util.*;

public class Test4{
	public static void main(String[] args){
        Vector<String> myVector1=new Vector<String>(Arrays.asList("1","1","1","1","1","4","1"));
        Vector<String> myVector2=new Vector<String>(Arrays.asList("1","1","3","1","2","4","1"));
        String[] result1=getElementFromVector(myVector1,3);
        String[] result2=getElementFromVector(myVector2,3);
        System.out.println(Arrays.toString(result1));
        System.out.println(Arrays.toString(result2));

	}
	public static String[] getElementFromVector(Vector<String> vector,int count){ 
		Set<String> mySet=new HashSet<String>(vector);
		String[] result=new String[count];
		int index=count-1;
		for(String str:mySet){
			if(index<0){
				break;
			}
			result[index--]=str;
		}
		if(index>=0){
			for(String str:vector){
				result[index--]=str;
				if(index<0){
					break;
				}
			}
		}
		return  result;
	}

}

F:\java>java Test4
[1, 4, 1]
[1, 2, 3]

[bigbug9002]

有bug.等一下.

[sunnyfun888]

[Quote=引用 10 楼 bigbug9002 的回复:]
有bug.等一下.
[/Quote]
刚想说
遇到
1,1,1,1,1,1,1,4,1那就从114取三个
1,1,1,1,1,1,1,1,1那就从111中取三个
就不对了

[dreamingdan]

我是在J2ME下写的,所以最好是用String ,String[], Vector来实现,其他的类型怕是不支持

[bigbug9002]

import java.util.*;

public class Test4{
	public static void main(String[] args){
        Vector<String> myVector1=new Vector<String>(Arrays.asList("4","1","1","1","1","1","1"));
        Vector<String> myVector2=new Vector<String>(Arrays.asList("1","1","3","1","2","4","1"));
        String[] result1=getElementFromVector(myVector1,3);
        String[] result2=getElementFromVector(myVector2,3);
        System.out.println(Arrays.toString(result1));
        System.out.println(Arrays.toString(result2));

	}
	public static String[] getElementFromVector(Vector<String> vector,int count){ 
		Map<String,Integer> myMap=new HashMap<String,Integer>();
		for(int i=0;i<vector.size();i++){
			myMap.put(vector.get(i),i);
		}
		String[] result=new String[count];
		int index=count-1;
		for(String str:myMap.keySet()){
			if(index<0){
				break;
			}
			result[index--]=str;
		}
		if(index>=0){
			boolean isAll=false;
			for(int i=0;i<vector.size()&&!isAll;i++){
				for(int j=count-1;j>index;j--){
					String str=vector.get(i);
					if(str.equals(result[j])&&myMap.get(str).intValue()!=i){
						result[index--]=str;
						if(index<0){
							isAll=true;
							break;
						}
					}
				}
			}
		}
		return  result;
	}

}

这个应该是没有问题的.

[bigbug9002]

j2me不支持Map?

[sunnyfun888]

Map应该有吧
简化一下算法：

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;

public class Test4{
    public static void main(String[] args){
    	Vector<String> myVector;
    	String[] result;
    	
        myVector=new Vector<String>(Arrays.asList("1","1","1","1","3","4","1"));
        result=getElementFromVector(myVector,3);
        System.out.println(Arrays.toString(result));
        
        myVector=new Vector<String>(Arrays.asList("1","1","1","1","1","4","1"));
        result=getElementFromVector(myVector,3);
        System.out.println(Arrays.toString(result));
        
        myVector=new Vector<String>(Arrays.asList("1","1","1","1","1","1","1"));
        result=getElementFromVector(myVector,3);
        System.out.println(Arrays.toString(result));

    }
    public static String[] getElementFromVector(Vector<String> vector,int count){ 
        String[] result=new String[count];

    	Map<String, Integer> myMap = new HashMap<String, Integer>();
		for(String str:vector){
			if(myMap.get(str) == null){
				myMap.put(str, 1);
			}else{
				myMap.put(str, myMap.get(str) + 1);
			}
		}
		
		while (count > 0){
		    for(String str : myMap.keySet()){
	            if(count <= 0){
	            	break;
	            }
	            if(myMap.get(str) > 0){
		            result[--count]= str;
		            myMap.put(str, myMap.get(str) - 1);
	            }
		    }
	    }
        return result;
    }
    
}