package com.bupt.syc;import java.util.Iterator;
import java.util.LinkedList;import org.junit.Test;public class Josephus {// 模拟解法public static int JosephusWinner(int M, int N) throws Exception {if (N < M) {throw new Exception("M should smaller than N");}int arr[] = new int[N];for (int i = 0; i < N; i++) {arr[i] = 1;}int cnt = 0, k = 0, j = 0;int num=-1;while(cnt<=N-1){if(arr[k]==1){j+=arr[k];}if(j==M){arr[k]=0;cnt++;}}return num;}//公式法//f(1)=0//f=(f+m)mod i (i>1)public static int JosephusWinner2(int M ,int N){int winner=0;for(int i=2;i<=N;i++){winner=(winner+M)%i;}return winner;}public static void JosephusWinner3(int M ,int N){LinkedList <Integer> linkedList=new LinkedList<Integer>();for(int i=0;i<N;i++){linkedList.add(i);}int num=0;while(linkedList.size()>1){Iterator iterator=linkedList.iterator();while(iterator.hasNext()){num++;iterator.next();if(num==M){iterator.remove();num=0;}}}if(linkedList.size()==1){System.out.println("winner is :"+linkedList.get(0));}}//题目：有N个人围成一圈，每人有一个编号，从编号为1的人开始，每隔M个出圈，按出圈次序排成一列，其编号刚好按顺序从1到M。 //要求：从键盘输入M，N，编程计算并输出这N个人原来在圈中的位置。public static void reverseJosephusWinner(int M,int N){LinkedList <Integer> linkedList=new LinkedList<Integer>();for(int i=0;i<N;i++){linkedList.add(0);}int num=1;int cnt=0;int index=0;while(num<=N){if(linkedList.get(index)==0){cnt++;}if(cnt==M&&linkedList.get(index)==0){linkedList.set(index, num);num++;cnt=0;for(int i=0;i<N;i++){System.out.print(linkedList.get(i)+" ");}System.out.println();}if(index+1>N-1) index=0;else index++;}}public static void main(String args[]) {JosephusWinner3(5,9);reverseJosephusWinner(5,9);}
}