卡片游戏(Throwing cards away I)

Problem B: Throwing cards away I

Given is an ordered deck of

n cards numbered 1 to

n with card 1 at the top and card

n at the bottom. The following operation is performed as long as there are at least two cards in the deck:

Throw away the top card and move the card that is now on the top of the deck to the bottom of the deck.

Your task is to find the sequence of discarded cards and the last, remaining card.

Each line of input (except the last) contains a number n ≤ 50. The last line contains 0 and this line should not be processed. For each number from the input produce two lines of output. The first line presents the sequence of discarded cards, the second line reports the last remaining card. No line will have leading or trailing spaces. See the sample for the expected format.

Sample input

7 19 10 6 0

Output for sample input

Discarded cards: 1, 3, 5, 7, 4, 2
Remaining card: 6
Discarded cards: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 4, 8, 12, 16, 2, 10, 18, 14
Remaining card: 6
Discarded cards: 1, 3, 5, 7, 9, 2, 6, 10, 8
Remaining card: 4
Discarded cards: 1, 3, 5, 2, 6
Remaining card: 4

Folklore, adapted by Piotr Rudnicki

【分析】

       模拟队列：卡片按编号1,2，...，n依次加入，按照规则从队头取出，再将新的队头取出加入到队尾。

用java语言编写程序，代码如下：

import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    
    int n;
    while(input.hasNext()) {
      n = input.nextInt();
      if(n == 0)
        break;
      
      Queue<Integer> q = new LinkedList<Integer>();
      for(int i = 1; i <= n; i++)
        q.add(i);
      
      System.out.print("Discarded cards:");
      boolean first = true;
      while(q.size() > 1) {
        if(first) {
          System.out.print(" " + q.poll());
          first = false;
        }
        else {
          System.out.print(", " + q.poll());
        }
        
        int temp = q.poll();
        q.add(temp);
      }
      System.out.println();
      System.out.println("Remaining card: " + q.peek());
    }
  }
}