一个ITAT大赛的试题（我的解法）
题目
给定一个字符串的集合，格式如：{aaa bbb ccc}， {bbb ddd}，
{eee fff}，{ggg}，{ddd hhh}，将其中交集不为空的集合合并，要
求合并完成后的集合之间无交集。例如上例应输出{aaa bbb ccc
ddd hhh}, {eee fff}, {ggg}
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Demo17
{
public Demo17 (){}
public static void main(String[] args)
{
Map<Integer,Integer> map = new HashMap<Integer,Integer>();//用于统计重复的 set在list中的 角标
List<HashSet<String>> al = new ArrayList<HashSet<String>>();//用于存放set
List<HashSet<String>> al2 = new ArrayList<HashSet<String>>();//用于存放set中含有交集的 set
List<HashSet<String>> al3 = new ArrayList<HashSet<String>>();//用于存放将有交集的合并后 存放在此set中
HashSet<String> list_last = new HashSet<String>();//将有交集的 存放在此set中
Set<String> s1 = new HashSet<String>();
s1.add("aaa");
s1.add("bbb");
s1.add("ccc");
Set<String> s2 = new HashSet<String>();
s2.add("bbb");
s2.add("ddd");
Set<String> s3 = new HashSet<String>();
s3.add("eee");
s3.add("fff");
Set<String> s4= new HashSet<String>();
s4.add("ggg");
Set<String> s5 = new HashSet<String>();
s5.add("ddd");
s5.add("hhh");
al.add((HashSet<String>) s1);
al.add((HashSet<String>) s2);
al.add((HashSet<String>) s3);
al.add((HashSet<String>) s4);
al.add((HashSet<String>) s5);
map = getResult(al);
merge(map, al, al2, al3, list_last);
al.removeAll(al2);
al.addAll(0,al3);
printList(al);
}
private static List<HashSet<String>> merge(Map<Integer,Integer> map,List<HashSet<String>> al,List<HashSet<String>> al2,List<HashSet<String>> al3,HashSet<String> list_last)
{
Set<Integer> keyset = map.keySet();
int key1 = -1;
int key2 = 0;
Iterator<Integer> it = keyset.iterator();
while(it.hasNext())
{
key1=key2;
key2 = it.next();
int value = map.get(key2);
if(!list_last.isEmpty())
{
list_last = new HashSet<String>();
}
if(key1!=-1&&key2==map.get(key1))
{
list_last.addAll(al.get(key2));
list_last.addAll(al.get(value));
al2.add(al.get(key2));
al2.add(al.get(value));
if(al3.size()-1>=0)
{
al3.get(al3.size()-1).addAll(list_last);
}
else
{ al3.add(list_last);
}
}else
{
list_last.addAll(al.get(key2));
list_last.addAll(al.get(value));
al2.add(al.get(key2));
al2.add(al.get(value));
al3.add(list_last);
}
}
return al;
}
private static Map<Integer,Integer> getResult( List<HashSet<String>> al)
{
Map<Integer,Integer> map = new HashMap<Integer,Integer>();
String str=null;
// HashSet<String>[] s = (HashSet<String> [])al.toArray();
System.out.println(al.size());
HashSet<String>[] s = new HashSet[al.size()] ;
al.toArray(s);
for (int i=0;i<s.length-1;i++)
{
for(int j=i+1;j<s.length;j++)
{
Iterator<String > it2 = s[j].iterator();
while(it2.hasNext())
{
str= it2.next();
if(s[i].contains(str))
{
map.put(i,j);
System.out.println(map);
break;
}
}
}
}
return map;
}
private static void printList(List<HashSet<String>> al)
{
Iterator <HashSet<String>> it = al.iterator();
while(it.hasNext())
{
HashSet<String> s = it.next();
String [] sarr =new String [s.size()];
s.toArray(sarr);
System.out.print("{");
for (int i = 0; i < sarr.length; i++)
{
if(i!=sarr.length-1)
System.out.print(sarr[i]+",");
else
System.out.print(sarr[i]);
}
System.out.print("}");
}
}
}
