首页 > 专题系列 > Java解POJ > POJ 1666 Candy Sharing Game [解题报告] Java
2013
11-10

POJ 1666 Candy Sharing Game [解题报告] Java

Candy Sharing Game

问题描述 :

A number of students sit in a circle facing their teacher in the center. Each student initially has an even number of pieces of candy. When the teacher blows a whistle, each student simultaneously gives half of his or her candy to the neighbor on the right. Any student, who ends up with an odd number of pieces of candy, is given another piece by the teacher. The game ends when all students have the same number of pieces of candy.

Write a program which determines the number of times the teacher blows the whistle and the final number of pieces of candy for each student from the amount of candy each child starts with.

输入:

The input may describe more than one game. For each game, the input begins with the number N of students,followed by N (even) candy counts for the children counter-clockwise around the circle. The input ends with a student count of 0. Each input number is on a line by itself.

输出:

For each game, output the number of rounds of the game followed by the amount of candy each child ends up with,both on one line.

样例输入:

6
36
2
2
2
2
2
11
22
20
18
16
14
12
10
8
6
4
2
4
2
4
6
8
0

样例输出:

15 14
17 22
4 8

温馨提示:

Notes:

The game ends in a finite number of steps because:

1. The maximum candy count can never increase.

2. The minimum candy count can never decrease.

3. No one with more than the minimum amount will ever decrease to the minimum.

4. If the maximum and minimum candy count are not the same, at least one student with the minimum amount must have their count increase

解题代码:

//* @author 洪晓鹏<[email protected]>
import java.util.Scanner;

public class Main {

/**
 * @param args
 */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  Scanner in = new Scanner(System.in);
  while (true) {
   int student = in.nextInt();
   if (0 == student)
	break;
   int[] candy = new int[student];
   for (int i = 0; i < student; i++) {
	candy[i] = in.nextInt();
   }
	int temp = 0;
	int turns = 0;
	while (true) {
           for (int i = 0; i < student; i++) {

	    if (i == 0) {
            	temp = (int) Math.ceil(candy[i] * 0.5);
		candy[i] = ((int) Math.ceil(candy[student - 1] * 0.5))
			+ temp;
             }

	else {
		int temp1 = (int) Math.ceil(candy[i] * 0.5);
		candy[i] = (int) Math.ceil(candy[i] * 0.5) + temp;
		temp = temp1;
	}
	}
		turns++;
		int numberOfCandy = candy[0] % 2 == 0 ? candy[0] : candy[0] + 1;
		int count = 0;
		for (int i = 0; i < student; i++) {
			if (candy[i] % 2 == 0 && candy[i] == numberOfCandy)
				count++;
			else if (candy[i] % 2 != 0
					&& (candy[i] + 1) == numberOfCandy)
				count++;
			else
				break;
		}
		if (count == student) {
			System.out.println(turns + " " + numberOfCandy);
			break;
		}
	}
  }
 }

}

  1. 你的理解应该是:即使主持人拿走一个箱子对结果没有影响。这样想,主持人拿走的箱子只是没有影响到你初始选择的那个箱子中有奖品的概率,但是改变了其余两个箱子的概率分布。由 1/3,1/3 变成了 0, 2/3