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											2018-10-10 18:03:03 -04:00
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							|  |  |  |  | id: 5900f4971000cf542c50ffa9 | 
					
						
							|  |  |  |  | challengeType: 5 | 
					
						
							|  |  |  |  | title: 'Problem 298: Selective Amnesia' | 
					
						
							|  |  |  |  | videoUrl: '' | 
					
						
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										 |  |  |  | localeTitle: 问题298:选择性健忘症 | 
					
						
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											2018-10-10 18:03:03 -04:00
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							|  |  |  |  | ## Description
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										 |  |  |  | <section id="description"> | 
					
						
							|  |  |  |  | 拉里(Larry)和罗宾(Robin)玩着一场记忆游戏,其中涉及一个随机数序列,介于1到10之间(含1和10),每次被召唤一个。每个玩家最多可以记住5个先前的数字。当被叫号码在玩家的记忆中时,该玩家将获得积分。如果不是,则播放器将被叫号码添加到他的记忆中,如果他的记忆已满,则删除另一个号码。 | 
					
						
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							|  |  |  |  | 两位选手都以空洞的回忆开始。两位玩家总是向他们的记忆中添加新的遗漏号码,但是在决定删除哪个号码时使用不同的策略: | 
					
						
							|  |  |  |  | 拉里(Larry)的策略是删除最长时间内未拨打的电话。 | 
					
						
							|  |  |  |  | Robin的策略是删除内存中时间最长的数字。 | 
					
						
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							|  |  |  |  | 范例游戏:Turn | 
					
						
							|  |  |  |  |   被叫号码 | 
					
						
							|  |  |  |  |   拉里的记忆 | 
					
						
							|  |  |  |  |   拉里的比分 | 
					
						
							|  |  |  |  |   罗宾的记忆 | 
					
						
							|  |  |  |  |   罗宾的分数 | 
					
						
							|  |  |  |  | 1个 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  | 2 | 
					
						
							|  |  |  |  |   2 | 
					
						
							|  |  |  |  |   1,2 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  |   1,2 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  | 3 | 
					
						
							|  |  |  |  |   4 | 
					
						
							|  |  |  |  |   1,2,4 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  |   1,2,4 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  | 4 | 
					
						
							|  |  |  |  |   6 | 
					
						
							|  |  |  |  |   1,2,4,6 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  |   1,2,4,6 | 
					
						
							|  |  |  |  |   0 | 
					
						
							|  |  |  |  | 5 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   1,2,4,6 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   1,2,4,6 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  | 6 | 
					
						
							|  |  |  |  |   8 | 
					
						
							|  |  |  |  |   1,2,4,6,8 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   1,2,4,6,8 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  | 7 | 
					
						
							|  |  |  |  |   10 | 
					
						
							|  |  |  |  |   1,4,6,8,10 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   2,4,6,8,10 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  | 8 | 
					
						
							|  |  |  |  |   2 | 
					
						
							|  |  |  |  |   1,2,6,8,10 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   2,4,6,8,10 | 
					
						
							|  |  |  |  |   2 | 
					
						
							|  |  |  |  | 9 | 
					
						
							|  |  |  |  |   4 | 
					
						
							|  |  |  |  |   1,2,4,8,10 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   2,4,6,8,10 | 
					
						
							|  |  |  |  |   3 | 
					
						
							|  |  |  |  | 10 | 
					
						
							|  |  |  |  |   1个 | 
					
						
							|  |  |  |  |   1,2,4,8,10 | 
					
						
							|  |  |  |  |   2 | 
					
						
							|  |  |  |  |   1,4,6,8,10 | 
					
						
							|  |  |  |  |   3 | 
					
						
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							|  |  |  |  | 用L表示拉里的分数,用R表示罗宾的分数,| L-R |的期望值是多少? 50转后?使用x.xxxxxxxx格式将答案四舍五入到小数点后八位。 | 
					
						
							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Instructions
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										 |  |  |  | <section id="instructions"> | 
					
						
							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Tests
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							|  |  |  |  | <section id='tests'> | 
					
						
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							|  |  |  |  | ```yml | 
					
						
							|  |  |  |  | tests: | 
					
						
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										 |  |  |  |   - text: <code>euler298()</code>应该返回1.76882294。 | 
					
						
							|  |  |  |  |     testString: assert.strictEqual(euler298(), 1.76882294); | 
					
						
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							|  |  |  |  | ``` | 
					
						
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							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Challenge Seed
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							|  |  |  |  | <section id='challengeSeed'> | 
					
						
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							|  |  |  |  | <div id='js-seed'> | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | function euler298() { | 
					
						
							|  |  |  |  |   // Good luck! | 
					
						
							|  |  |  |  |   return true; | 
					
						
							|  |  |  |  | } | 
					
						
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							|  |  |  |  | euler298(); | 
					
						
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							|  |  |  |  | ``` | 
					
						
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							|  |  |  |  | </div> | 
					
						
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							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Solution
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							|  |  |  |  | <section id='solution'> | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | // solution required | 
					
						
							|  |  |  |  | ``` | 
					
						
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							|  |  |  |  | /section> |