回答編集履歴
2
追記
answer
CHANGED
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@@ -1,2 +1,74 @@
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1
1
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`nums[0]`と`nums[num.length-1]`をスワップすればいいと思いますよ。
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2
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-
負号が付いていれば`nums[1]`ですね。
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2
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+
負号が付いていれば`nums[1]`ですね。
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3
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+
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4
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書いてみた
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5
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+
---
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6
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元のコードと全く違いますが。
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7
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```Java
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8
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import java.util.NoSuchElementException;
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9
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import java.util.Scanner;
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10
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+
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11
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class ReverseInt {
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12
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static String lstrip(String src, String removeChars) {
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13
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return src.replaceFirst(
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14
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String.format("^[%s]+", removeChars), ""
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15
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);
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16
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}
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17
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static StringBuilder lstrip(StringBuilder src, String removeChars) {
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18
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return new StringBuilder(
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19
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lstrip(src.toString(), removeChars)
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20
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);
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21
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}
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22
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+
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23
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static String reverse(String input) throws NumberFormatException {
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24
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Integer.parseInt(input);
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25
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StringBuilder builder = new StringBuilder(input);
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26
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27
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boolean isNegative = builder.toString().startsWith("-");
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28
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if(isNegative) {
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29
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builder = builder.deleteCharAt(0);
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30
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}
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31
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32
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builder.reverse();
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33
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builder = lstrip(builder, "0");
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34
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35
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if(isNegative) {
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36
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builder.insert(0, "-");
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37
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}
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38
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39
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return builder.toString();
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40
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}
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41
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+
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42
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public static void main(String[] args) {
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43
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try(Scanner sc = new Scanner(System.in)) {
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44
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while(sc.hasNext()) {
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45
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String input = sc.nextLine();
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46
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try {
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47
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System.out.println(reverse(input));
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48
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}
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49
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catch(NumberFormatException e) {
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50
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System.out.println("\"" + input + "\" cannot be interpreted as an integer.");
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51
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}
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52
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}
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53
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}
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54
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}
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55
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}
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56
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```
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57
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+
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58
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+
**入力例**
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59
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```plain
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60
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12345
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61
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-123
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62
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hoge
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63
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1000
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64
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-100
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65
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```
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66
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+
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67
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**出力例** [Wandbox](https://wandbox.org/permlink/bgWclCumxPyILXE1)
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68
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```plain
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69
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54321
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70
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+
-321
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71
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"hoge" cannot be interpreted as an integer.
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72
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1
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73
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-1
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74
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```
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1
負数の判定忘れてた
answer
CHANGED
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@@ -1,1 +1,2 @@
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1
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-
`nums[0]`と`nums[num.length-1]`をスワップすればいいと思いますよ。
|
|
1
|
+
`nums[0]`と`nums[num.length-1]`をスワップすればいいと思いますよ。
|
|
2
|
+
負号が付いていれば`nums[1]`ですね。
|