130 lines
2.0 KiB
Markdown
130 lines
2.0 KiB
Markdown
---
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id: 5900f4971000cf542c50ffa9
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challengeType: 5
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title: 'Problem 298: Selective Amnesia'
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---
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## Description
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<section id='description'>
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Larry and Robin play a memory game involving of a sequence of random numbers between 1 and 10, inclusive, that are called out one at a time. Each player can remember up to 5 previous numbers. When the called number is in a player's memory, that player is awarded a point. If it's not, the player adds the called number to his memory, removing another number if his memory is full.
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Both players start with empty memories. Both players always add new missed numbers to their memory but use a different strategy in deciding which number to remove:
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Larry's strategy is to remove the number that hasn't been called in the longest time.
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Robin's strategy is to remove the number that's been in the memory the longest time.
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Example game:Turn
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Callednumber
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Larry'smemory
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Larry'sscore
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Robin'smemory
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Robin'sscore
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1
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1
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1
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0
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1
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0
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2
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2
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1,2
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0
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1,2
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0
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3
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4
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1,2,4
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0
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1,2,4
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0
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4
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6
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1,2,4,6
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0
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1,2,4,6
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0
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5
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1
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1,2,4,6
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1
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1,2,4,6
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1
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6
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8
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1,2,4,6,8
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1
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1,2,4,6,8
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1
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7
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10
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1,4,6,8,10
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1
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2,4,6,8,10
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1
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8
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2
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1,2,6,8,10
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1
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2,4,6,8,10
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2
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9
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4
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1,2,4,8,10
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1
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2,4,6,8,10
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3
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10
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1
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1,2,4,8,10
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2
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1,4,6,8,10
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3
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Denoting Larry's score by L and Robin's score by R, what is the expected value of |L-R| after 50 turns? Give your answer rounded to eight decimal places using the format x.xxxxxxxx .
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>euler298()</code> should return 1.76882294.
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testString: 'assert.strictEqual(euler298(), 1.76882294, "<code>euler298()</code> should return 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
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function euler298() {
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// Good luck!
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return true;
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}
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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
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// solution required
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```
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</section>
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