题目:有 n 个人围成一圈,顺序排号,从第一个开始报数(从1到3报数),凡报到 3 的人退出圈子,问最后最后留下的是原来第几号的那位。 提示:用数组完成
import java.util.ArrayList; import java.util.List; import java.util.ListIterator; import java.util.Scanner; public class DequeueNumThree { //数组 public static void MethodArr(){ System.out.println("Please input total people : "); Scanner scanner = new Scanner(System.in); int totalPeople = scanner.nextInt(); boolean[] arr = new boolean[totalPeople]; for(int i = 0; i < arr.length; i++){ arr[i] = true; } int count = 0;//报数 1 2 3 int leftPeople = totalPeople;//去掉报道3之后剩余的人数 int index = 0;//数组下标 while(leftPeople > 1){//最后只能剩余一个人 if(arr[index] == true){//如果当前状态为true count++;//报数 if(count == 3){//如果报数为3 arr[index] = false;//状态设置成false count = 0;//为下次重新报数做准备 leftPeople--;//剩余人数减一 } } index++;//到下一个人了 if(index == totalPeople){//如果到最后一个人了，那么，从头重新开始报数 index = 0; } } for(int i = 0; i < totalPeople; i++){ if(arr[i] == true){ System.out.println("last number is " + (i+1)); } } } //容器 public static void MethodCollection(){ final int peoplesNum = 10; final int three = 3; List<Integer> peopleList = new ArrayList<Integer>(); for(int i=0; i<peoplesNum; i++){ peopleList.add(i+1); } System.out.println("total num of people : "+peopleList.size()); int count = 1; ListIterator<Integer> iter = null; while(peopleList.size() > 1){ iter = peopleList.listIterator();//循环一次，更新一次iter while(iter.hasNext()){ int i = iter.next(); System.out.println("now is " + i); if(count++ % three == 0){ iter.remove(); count = 1; System.out.println(i+"------>out!"); } } } System.out.println("\nlast people is "+peopleList); } public static void main(String[] args) { MethodArr(); // MethodCollection(); } }