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class TstNode(object): |
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key = None |
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value = None |
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mid = None |
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left = None |
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right = None |
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8
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def __init__(self, key=None, value=None, left=None, right=None, mid=None): |
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if key is not None: |
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self.key = key |
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if value is not None: |
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self.value = value |
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if mid is not None: |
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self.mid = mid |
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if left is not None: |
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self.left = left |
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if right is not None: |
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self.right = right |
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def char_at(s, index): |
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if len(s) <= index: |
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return -1 |
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return ord(s[index]) |
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class TernarySearchTrie(object): |
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root = None |
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N = 0 |
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31
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def put(self, key, value): |
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self.root = self._put(self.root, key, value, 0) |
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34
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def _put(self, x, key, value, d): |
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c = char_at(key, d) |
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if x is None: |
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x = TstNode(key=c, value=None) |
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compared = c - x.key |
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if compared < 0: |
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x.left = self._put(x.left, key, value, d) |
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elif compared > 0: |
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x.right = self._put(x.right, key, value, d) |
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else: |
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if len(key) - 1 > d: |
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x.mid = self._put(x.mid, key, value, d + 1) |
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else: |
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if x.value is None: |
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self.N += 1 |
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x.value = value |
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return x |
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51
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52
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def get(self, key): |
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x = self._get(self.root, key, 0) |
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if x is None: |
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return None |
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return x.value |
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58
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def _get(self, x, key, d): |
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c = char_at(key, d) |
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if x is None: |
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return None |
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compared = c - x.key |
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63
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if compared < 0: |
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return self._get(x.left, key, d) |
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elif compared > 0: |
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return self._get(x.right, key, d) |
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else: |
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if len(key) - 1 > d: |
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return self._get(x.mid, key, d + 1) |
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else: |
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return x |
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73
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def delete(self, key): |
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self.root = self._delete(self.root, key, 0) |
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76
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def _delete(self, x, key, d): |
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if x is None: |
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return None |
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79
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c = char_at(key, d) |
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80
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compared = c - x.key |
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81
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if compared < 0: |
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82
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x.left = self._delete(x.left, key, d) |
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83
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elif compared > 0: |
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84
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x.right = self._delete(x.right, key, d) |
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85
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else: |
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86
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if len(key) - 1 > d: |
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87
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x.mid = self._delete(x.mid, key, d + 1) |
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88
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else: |
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89
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self.N -= 1 |
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90
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x = None |
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91
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return x |
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92
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93
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def contains_key(self, key): |
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94
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x = self._get(self.root, key, 0) |
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95
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if x is None: |
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96
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return False |
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97
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return True |
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98
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99
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def size(self): |
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100
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return self.N |
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101
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102
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def is_empty(self): |
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103
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return self.N == 0 |
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104
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105
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def keys(self): |
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106
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queue = [] |
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107
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self.collect(self.root, '', queue) |
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108
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return queue |
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109
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110
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def values(self): |
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111
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queue = [] |
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112
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self.collect_values(self.root, queue) |
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113
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114
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def collect(self, x, prefix, queue): |
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115
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if x is None: |
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116
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return |
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117
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if x.value is not None: |
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118
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queue.append(prefix + chr(x.key)) |
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119
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self.collect(x.left, prefix, queue) |
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120
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self.collect(x.mid, prefix + chr(x.key), queue) |
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121
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self.collect(x.right, prefix, queue) |
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122
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123
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def collect_values(self, x, queue): |
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124
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if x is None: |
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125
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return |
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126
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if x.value is not None: |
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127
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queue.append(x.value) |
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128
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129
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self.collect_values(x.left, queue) |
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130
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self.collect_values(x.mid, queue) |
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131
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self.collect_values(x.right, queue) |
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132
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|
133
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|
134
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class TernarySearchSet(TernarySearchTrie): |
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135
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def add(self, key): |
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136
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self.put(key, 0) |
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137
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|
138
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def contains(self, key): |
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139
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return self.contains_key(key) |
|
140
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141
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def to_array(self): |
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142
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return self.keys() |
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143
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chen0040 /
pysie
