回答編集履歴
1
ちょうせい
test
CHANGED
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@@ -9,3 +9,39 @@
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9
9
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console.log(result);
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10
10
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11
11
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```
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12
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13
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# 分解したサンプル
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14
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15
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16
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17
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```javascript
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18
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19
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const lines=[1,4,12,20,27];
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20
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21
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const result=lines.reduce((accumulator,currentValue,index)=>{
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22
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23
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console.log([accumulator,currentValue,index]);//デバグ用
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24
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25
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let arr;
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26
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27
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if(accumulator instanceof Array){
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28
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29
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arr=accumulator;
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30
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31
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}else{
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32
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arr=[];
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34
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35
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}
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36
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37
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let previousValue=lines[index-1];
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38
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39
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arr=arr.concat([currentValue-previousValue]);
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40
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41
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return arr;
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42
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});
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44
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45
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console.log(result);
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46
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47
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```
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