回答編集履歴
1
追記
test
CHANGED
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@@ -59,3 +59,65 @@
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59
59
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a b * c +
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60
60
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61
61
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```
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62
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+
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63
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+
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64
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+
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65
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+
**追記**
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66
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+
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67
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StringBuilder に追加していきたいのなら、
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68
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+
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69
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```Java
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70
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+
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71
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+
class Node {
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72
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+
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73
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public String expression; // 演算子または項
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74
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+
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75
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public Node left = null; // 左の子ノード
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76
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+
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77
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public Node right = null; // 右の子ノード
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78
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+
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79
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80
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+
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81
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Node(String e) { expression = e; }
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82
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+
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83
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Node(String e, Node l, Node r) { expression = e; left = l; right = r; }
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84
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+
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85
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+
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86
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87
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public void traversePostorder(StringBuilder rt) {
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88
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+
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89
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if (left != null) left.traversePostorder(rt);
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90
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+
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91
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if (right != null) right.traversePostorder(rt);
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92
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93
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rt.append(expression + " ");
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94
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+
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95
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}
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96
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+
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97
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}
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98
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+
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99
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+
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100
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+
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101
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class Main {
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102
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103
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public static void main(String args[]) {
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104
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105
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Node root = new Node("+",
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106
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107
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new Node("*", new Node("a"), new Node("b")),
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108
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109
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new Node("c")
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110
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+
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111
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);
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112
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113
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StringBuilder sb = new StringBuilder();
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114
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115
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root.traversePostorder(sb);
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116
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+
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117
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System.out.println(sb);
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118
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+
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119
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}
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120
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+
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121
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}
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122
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+
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123
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```
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