回答編集履歴
1
追記
answer
CHANGED
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@@ -28,4 +28,35 @@
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28
28
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実行結果
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29
29
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```text
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30
30
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a b * c +
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31
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+
```
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32
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+
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33
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+
**追記**
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34
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+
StringBuilder に追加していきたいのなら、
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35
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```Java
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36
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class Node {
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37
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public String expression; // 演算子または項
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38
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public Node left = null; // 左の子ノード
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39
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public Node right = null; // 右の子ノード
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40
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+
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41
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Node(String e) { expression = e; }
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42
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Node(String e, Node l, Node r) { expression = e; left = l; right = r; }
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43
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+
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44
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public void traversePostorder(StringBuilder rt) {
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45
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if (left != null) left.traversePostorder(rt);
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46
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if (right != null) right.traversePostorder(rt);
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47
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rt.append(expression + " ");
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48
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}
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49
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}
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50
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+
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51
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class Main {
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52
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public static void main(String args[]) {
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53
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Node root = new Node("+",
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54
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new Node("*", new Node("a"), new Node("b")),
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55
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new Node("c")
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56
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);
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57
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StringBuilder sb = new StringBuilder();
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58
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root.traversePostorder(sb);
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59
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System.out.println(sb);
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60
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}
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61
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}
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31
62
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```
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