74 lines
2.2 KiB
Python
74 lines
2.2 KiB
Python
"""Hash tabuľka s lineárnym sondovaním a reťazcovými kľúčmi."""
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from unittest import result
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class HashTable:
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def __init__(self, capacity=10):
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"""Vytvor prázdnu tabuľku s kladnou celočíselnou kapacitou."""
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self.empty = object()
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self.deleted = object()
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self._capacity = capacity
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self.size = 0
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self.table = []
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for i in range(capacity):
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self.table.append(self.empty)
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@property
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def capacity(self):
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"""Vráť aktuálny počet pozícií v poli."""
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return self._capacity
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def hash(self, key):
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"""Vráť polynomiálny hash kľúča modulo aktuálna kapacita."""
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result = 0
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for char in str(key):
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result = result * 31 + ord(char)
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return result % self.capacity
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def probe(self, key):
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"""Vráť index kľúča alebo miesta na vloženie bez zmeny tabuľky."""
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i = 0
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while i < self.capacity:
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index = (self.hash(key) + i) % self.capacity
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if self.table[index] is self.empty:
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return index
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elif self.table[index] is not self.deleted and self.table[index][0] == key:
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return index
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i += 1
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raise KeyError(key)
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def load_factor(self):
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"""Vráť podiel počtu aktívnych položiek a kapacity."""
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return self.size / self.capacity if self._capacity > 0 else 0
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def __getitem__(self, key):
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index = self.probe(key)
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return self.table[index][1]
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def __setitem__(self, key, value):
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index = self.probe(key)
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if self.table[index] is self.empty:
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self.size += 1
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self.table[index] = (key, value)
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def __delitem__(self, key):
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index = self.probe(key)
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if self.table[index] is not self.empty:
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self.table[index] = self.deleted
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self.size -= 1
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def __contains__(self, key):
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try:
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self.probe(key)
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return True
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except KeyError:
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return False
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def __len__(self):
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return self.size
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def __iter__(self):
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for bucket in self.table:
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if bucket is not self.empty:
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yield bucket[0]
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