约瑟夫环问题

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

public class Test {

/**
* @param args
*/
public static void main(String[] args) {
Map map = new HashMap();
for(int i =1;i<=41;i++){
map.put(Integer.valueOf(i), Integer.valueOf(i));
}
Test t = new Test();
Map map0 = t.select(map,map.size()/3);
Iterator iter = map0.keySet().iterator();
while(iter.hasNext()){
Object key =iter.next();
System.out.println("+++++++++剩余的数字="+map0.get(key));
}
}

public Map select(Map map0,int index){
Map map = new HashMap();
int j = 1;
int k = 0;
int size = map0.size();
boolean flag = true;
if(size == 2){
return map0;
}
for(int i =1 ;i<=size;i++){
if(i%3==0&&flag){
System.out.println("+++++++++remove="+map0.get(Integer.valueOf(i)));
map0.remove(Integer.valueOf(i));
k++;
}
if(k == index){
flag = false;
if(map0.get(Integer.valueOf(i)) != null){
System.out.println("+++++++++put="+map0.get(Integer.valueOf(i)));
map.put(Integer.valueOf(j), map0.get(Integer.valueOf(i)));
map0.remove(Integer.valueOf(i));
j++;
}
}
}
Object[] key = map0.keySet().toArray();
    Arrays.sort(key);
    for(int i = 0; i < key.length; i++) {
    if(map0.get(key[i]) != null){
        map.put(Integer.valueOf(j), map0.get(key[i]));
System.out.println("+++++++++put="+map0.get(key[i]));
j++;
    }
    }
System.out.println("++++++++++map.size="+map.size());
return select(map,map.size()/3);
}
}