约瑟夫环-Java兑现

import java.util.HashMap;
import java.util.Map;

/**
 * 约瑟夫环--Java实现<br>
 * 有N个同学围成一圈，从1开始依次编号，从第P个开始报数，报到第T个时，该同学出列，<br>
 * 然后从下一个同学开始报数，仍是报到T个出列，如此重复下去，<br>
 * 直到所有的同学都出列（ 总人数不足T个时将循环报数），求同学出列的顺序。<br>
 * 
 * @author Administrator
 * 
 */
public class Joseph {

	public Map<Integer, Person> members = new HashMap<Integer, Person>();

	public String getJoseph(int n, int p, int t) {
		StringBuffer str = new StringBuffer();
		// 构造环
		for (int i = 1; i <= n; i++) {
			Person pn = new Person(i);
			if (i == 1) {
				pn.setBack(n);
			} else if (i == n) {
				pn.setNext(1);
			}
			members.put(i, pn);
		}
		// 当前同学
		Person current = members.get(p);
		// 开始报数
		while (n >= 1) {
			for (int i = 1; i <= t - 1; i++) {
				current = members.get(current.getNext());
				if (i == t - 1) {
					// 切换前后关系
					int back = current.getBack();
					int next = current.getNext();
					Person pastPerson = members.get(back);
					pastPerson.setNext(next);
					Person nextPerson = members.get(next);
					nextPerson.setBack(back);
					// 移除对象，并记录
					members.remove(current.getPosition());
					str.append(current.getPosition());
					if (n != 1) {
						str.append(",");
					}
					// 重新设置下一位为当前对象
					current = null;
					current = nextPerson;
				}
			}
			n--;
		}
		return str.toString();
	}
}

public class Person {

	private int back;// 上一位的位置
	private int position;// 我的位置
	private int next;// 下一位的位置

	public Person() {

	}

	public Person(int i) {
		back = i - 1;
		position = i;
		next = i + 1;
	}

	public int getBack() {
		return back;
	}

	public void setBack(int past) {
		this.back = past;
	}

	public int getPosition() {
		return position;
	}

	public void setPosition(int position) {
		this.position = position;
	}

	public int getNext() {
		return next;
	}

	public void setNext(int next) {
		this.next = next;
	}

}

@Test
public class JosephTest extends BaseTest{

	Joseph joseph = new Joseph();

	public void testCount(){
		String str= joseph.getJoseph(5, 2, 3);
		want.string(str).isEqualTo("4,2,1,3,5");
	}
}