实践题目：保龄球比赛计分
保龄球比赛一般分十局，每局最多可扔两个球，如果第一个球将所有的瓶子打倒了，就没必要打第二个球。但每局的计分可能会依赖后面的扔球得分，即如果这局扔第一个球得了10分，我们称全中，那个这局的得分=10分+后面扔的两球的得分，如果这局扔两球共得10分，我们称补中，那个这局的得分=10分+后面扔的一球的得分。

如下为敏捷培训时教练画的图：

答案有很多种，如下是我个人的做法，具体过程就不展示了。直接附上代码：

BowlingGameTest.java

package com.bijian.study.bowling.test;

import org.junit.Assert;
import org.junit.Test;

import com.bijian.study.bowling.Game;

public class BowlingGameTest {

	@Test
	public void normal_roll_should_return_sum_of_tow_rolls() {
		Game game = new Game(20);
		game.roll(4);
		game.roll(5);
		Assert.assertEquals(4+5,game.getFramescore(1));
		Assert.assertEquals(4+5,game.getTotalscore());
	}
	
	@Test
	public void spare_roll_should_return_sum_contain_next_roll() {
		Game game = new Game(20);
		game.roll(5);
		game.roll(5);
		game.roll(4);
		game.roll(5);
		Assert.assertEquals(5+5+4,game.getFramescore(2));
		Assert.assertEquals((5+5+4)+(4+5),game.getTotalscore());
	}
	
	@Test
	public void strike_roll_should_return_sum_contain_next_two_rolls() {
		Game game = new Game(20);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		Assert.assertEquals(10+5+4,game.getFramescore(1));
		Assert.assertEquals(5+4,game.getFramescore(2));
		Assert.assertEquals((10+5+4)+(5+4),game.getTotalscore());
	}
	
	@Test
	public void last_normal_roll_should_return_last_frame() {
		Game game = new Game(20);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(3);
		game.roll(4);
		game.roll(10);
		game.roll(3);
		game.roll(3);
		game.roll(0);
		game.roll(3);
		game.roll(2);
		game.roll(8);
		game.roll(10);
		game.roll(10);
		game.roll(2);
		game.roll(3);
		Assert.assertEquals(10+5+4,game.getFramescore(2));
		Assert.assertEquals(3+4,game.getFramescore(3));
		Assert.assertEquals(10+3+3,game.getFramescore(4));
		Assert.assertEquals(3+3,game.getFramescore(5));
		Assert.assertEquals(0+3,game.getFramescore(6));
		Assert.assertEquals(2+8+10,game.getFramescore(7));
		Assert.assertEquals(10+10+2,game.getFramescore(8));
		Assert.assertEquals(10+2+3,game.getFramescore(9));
		Assert.assertEquals(2+3,game.getFramescore(10));
		Assert.assertEquals((10+5+4)+(5+4)+(3+4)+(10+3+3)+(3+3)+(0+3)+(2+8+10)+(10+10+2)+(10+2+3)+(2+3),game.getTotalscore());
	}
	
	@Test
	public void last_spare_roll_should_return_last_frame_with_add_one_roll() {
		Game game = new Game(20);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(0);
		game.roll(0);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(10);
		game.roll(2);
		game.roll(8);
		game.roll(9);
		Assert.assertEquals(2+8+9,game.getFramescore(10));
		Assert.assertEquals((10+5+4)+(5+4)+(10+5+4)+(5+4)+(0+0)+(10+5+4)+(5+4)+(10+10+2)+(10+2+8)+(2+8+9),game.getTotalscore());
	}
	
	@Test
	public void last_strike_roll_should_return_last_frame_with_add_two_roll() {
		Game game = new Game(20);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(8);
		game.roll(2);
		
		//多投算无效球
		game.roll(3);
		
		Assert.assertEquals(10+5+4,game.getFramescore(2));
		Assert.assertEquals(10+10+10,game.getFramescore(3));
		Assert.assertEquals(10+10+10,game.getFramescore(4));
		Assert.assertEquals(10+10+5,game.getFramescore(5));
		Assert.assertEquals(10+5+4,game.getFramescore(6));
		Assert.assertEquals(5+4,game.getFramescore(7));
		Assert.assertEquals(10+10+10,game.getFramescore(8));
		Assert.assertEquals(10+10+8,game.getFramescore(9));
		Assert.assertEquals(10+8+2,game.getFramescore(10));
		
		//只有10局
		Assert.assertEquals(0,game.getFramescore(11));
		
		Assert.assertEquals((10+5+4)+(5+4)+(10+10+10)+(10+10+10)+(10+10+5)+(10+5+4)+(5+4)+(10+10+10)+(10+10+8)+(10+8+2),game.getTotalscore());
	}
	
	@Test
	public void last_strike_roll_should_return_last_frame_with_add_two_max_score_roll() {
		Game game = new Game(20);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(5);
		game.roll(5);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(5);
		game.roll(4);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		
		//多投无效球
		game.roll(10);
		
		Assert.assertEquals(0+0,game.getFramescore(1));
		Assert.assertEquals(0+0,game.getFramescore(2));
		Assert.assertEquals(0+0,game.getFramescore(3));
		Assert.assertEquals(5+5+5,game.getFramescore(4));
		Assert.assertEquals(5+4,game.getFramescore(8));
		Assert.assertEquals(10+10+10,game.getFramescore(9));
		Assert.assertEquals(10+10,game.getFramescore(10));
		Assert.assertEquals((0+0)+(0+0)+(0+0)+(5+5+5)+(5+4)+(10+5+4)+(5+4)+(10+10+10)+(10+10+10)+(10+10),game.getTotalscore());
	}
	
	@Test
	public void all_strike_roll_should_return_all_roll_with_last_two_max_score() {
		Game game = new Game(20);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		game.roll(10);
		
		//多投算无效球
		game.roll(5);
		
		Assert.assertEquals(10+10+10,game.getFramescore(1));
		Assert.assertEquals(10+10+10,game.getFramescore(4));
		Assert.assertEquals(10+10+10,game.getFramescore(6));
		Assert.assertEquals(10+10+10,game.getFramescore(10));
		Assert.assertEquals((10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10+10)+(10+10),game.getTotalscore());
	}
	
	@Test
	public void all_zero_roll_should_return_zero_score() {
		Game game = new Game(20);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		game.roll(0);
		Assert.assertEquals(0+0+0,game.getFramescore(1));//0
		Assert.assertEquals(0+0+0,game.getFramescore(2));//0
		Assert.assertEquals(0+0+0,game.getFramescore(3));//0
		Assert.assertEquals(0+0+0,game.getFramescore(4));//0
		Assert.assertEquals(0+0+0,game.getFramescore(5));//0
		Assert.assertEquals(0+0+0,game.getFramescore(6));//0
		Assert.assertEquals(0+0+0,game.getFramescore(7));//0
		Assert.assertEquals(0+0+0,game.getFramescore(8));//0
		Assert.assertEquals(0+0+0,game.getFramescore(9));//0
		Assert.assertEquals(0+0+0,game.getFramescore(10));//0
		Assert.assertEquals((0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0) + (0+0+0),game.getTotalscore());
	}
}

Game.java

package com.bijian.study.bowling;

/**
 * 保龄球比赛，计算每局分数及总分
 * 实现方法：
 * 采用rollscore数组记录比赛每次投球的分数，如果在一局当中，第一个球为满分的话，第二个球无需投，但在此数组中将其设置为0
 * 采用rollscoreState数组记录rollscore对应的下标是真实的分数还是免投设置的值
 * 
 * @author BIJIAN
 */
public class Game {
	
	//满分值
	public static int MAX_score = 10;
	//记录比赛每次投球的分数，如果在一局当中，第一个球为满分的话，第二个球无需投，但在此数组中将其设置为0
	private int[] rollscore;
	//rollscoreState记录rollscore对应的下标是真实的分数还是免投设置的值
	private boolean[] rollscoreState;
	//num为2*实际比赛的局数
	private int num;
	//投球的下标记数器
	private int currentRoll;
	
	/*
	 * 构造方法
	 */
	public Game(int num) {
		this.num = num;
		rollscore = new int[num+4];
		rollscoreState = new boolean[num+2];
		this.currentRoll = 0;
	}
	
	/*
	 * 投球
	 */
	public void roll(int pin) {
		if(currentRoll >= num + 2) {
			return;
		}
		if(currentRoll > num && rollscore[currentRoll-1] == MAX_score) {
			return;
		}
		rollscore[currentRoll++] = pin;
		if(pin == MAX_score && currentRoll < num) {
			rollscore[currentRoll] = 0;
			rollscoreState[currentRoll++] = true;
		}
	}
	
	/*
	 * 获取指定局次的分数
	 */
	public int getFramescore(int frame) {
		if(frame > num /2) {
			return 0;
		}
		int res = rollscore[(frame-1)*2] + rollscore[(frame-1)*2 + 1];
		if(rollscore[(frame-1)*2] == MAX_score) {
			res += rollscore[frame*2] + rollscore[frame*2 + 1];
			if(rollscore[frame*2] == MAX_score && rollscoreState[(frame-1)*2 + 1]) {
				res += rollscore[(frame+1)*2];
			}
		}else if(res == MAX_score) {
			res += rollscore[frame*2];
		}
		return res;
	}
	
	/*
	 * 获取比赛总分
	 */
	public int getTotalscore() {
		int totalscore = 0;
		for(int i=1;i<=currentRoll/2;i++) {
			if(i <= this.num/2) {
				totalscore += getFramescore(i);
			}
		}
		return totalscore;
	}
}