关于一个java算法的有关问题(急)

关于一个java算法的问题(急)
List   mainList=new   ArrayList();
String[]   first={ "key1 ", "value1 "};
String[]   second={ "key2 ", "value2 "};
String[]   third={ "key3 ", "value3 "};
String[]   four={ "key1 ", "value12 "};
String[]   five={ "key2 ", "value22 "};
String[]   six={ "key1 ", "value13 "};
String[]   seven={ "key4 ", "value4 "};
String[]   eight={ "key3 ", "value31 "};
String[]   nine={ "key1 ", "value14 "};
String[]   ten={ "key5 ", "value5 "};
mainList.add(first);
mainList.add(second);
mainList.add(third);
mainList.add(four);
mainList.add(five);
mainList.add(six);
mainList.add(seven);
mainList.add(eight);
mainList.add(nine);
mainList.add(ten);
Map   omap=new   HashMap();
我现在要把list里的属于同一个key(如“key1”)的value值(如： "value1 ", "value12 ", "value13 ", "value14 ")放在同一个list里,然后在放到omap里。最后omap里应该是   key                   value(List)
                                  key1                 value1,value12,value13,value14
                                  key2                 value2,value22
                                  key3                 value3,value31
                                  key4                 value4
                                  key5                 value5

请教各位有什么好的算法可以实现，谢谢！
另望有关于java算法的教材下载的话希望能给我发一本，我的邮箱是bernerhuang@ncsi.com.cn

------解决方案--------------------
up
------解决方案--------------------
呵呵，昨天才写过的一个算法，伪代码如下:

for(each ml in mainList){
List l = omap.get(ml[0]);
if(l==null){
l=new ArrayList();
omap.put(ml[0],l);
}
l.add(ml[1]);
}
------解决方案--------------------
loop(mainList){
1. get: key, value from mainList;
2. get the List(list) from omap;
3. if(list == null) list = new List();
4. list.add(value);
5. omap.put(key,list);
}
------解决方案--------------------
HashtableTest.java
======================
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;

public class HashtableTest {
private ArrayList mainList = new ArrayList();
private Hashtable omap=new Hashtable();

public ArrayList getMainList() {
return mainList;
}

public void setMainList(ArrayList mainList) {
this.mainList = mainList;
}

public Hashtable getOmap() {
return omap;