119 lines
3.4 KiB
Python
119 lines
3.4 KiB
Python
class HashTable:
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def __init__(self, capacity=10):
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if type(capacity) is not int:
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raise TypeError("Kapacita musí byť celé číslo (int)")
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if capacity <= 0:
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raise ValueError("Kapacita musí byť kladné číslo")
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self.__capacity = capacity
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self._size = 0
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self.empty = object()
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self.deleted = object()
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self.slots = [self.empty] * self.__capacity
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@property
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def capacity(self):
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return self.__capacity
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def _check_key(self, key):
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if not isinstance(key, str):
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raise TypeError("Kľúč musí byť reťazec (str)")
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def hash(self, key):
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self._check_key(key)
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h = 0
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for char in key:
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h = (31 * h + ord(char)) % self.__capacity
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return h
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def probe(self, key):
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self._check_key(key)
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start_index = self.hash(key)
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first_deleted = None
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for krok in range(self.__capacity):
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index = (start_index + krok) % self.__capacity
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slot = self.slots[index]
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if slot is self.empty:
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if first_deleted is not None:
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return first_deleted
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return index
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elif slot is self.deleted:
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if first_deleted is None:
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first_deleted = index
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else:
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if slot[0] == key:
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return index
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if first_deleted is not None:
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return first_deleted
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raise RuntimeError("Tabuľka je plná")
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def load_factor(self):
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return self._size / self.__capacity
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def _resize(self):
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old_slots = self.slots
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self.__capacity *= 2
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self.slots = [self.empty] * self.__capacity
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self._size = 0
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for slot in old_slots:
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if slot is not self.empty and slot is not self.deleted:
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key, value = slot
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index = self.probe(key)
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self.slots[index] = (key, value)
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self.size += 1
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def __getitem__(self, key):
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self._check_key(key)
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idx = self.probe(key)
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slot = self.slots[idx]
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if slot is not self.empty and slot is not self.deleted and slot[0] == key:
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return slot[1]
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raise KeyError(key)
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def __setitem__(self, key, value):
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self._check_key(key)
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idx = self.probe(key)
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slot = self.slots[idx]
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if slot is not self.empty and slot is not self.deleted and slot[0] == key:
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self.slots[idx] = (key, value)
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return
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if (self._size + 1) / self.__capacity > 0.7:
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self._resize()
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idx = self.probe(key)
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self.slots[idx] = (key, value)
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self._size += 1
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def __delitem__(self, key):
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self._check_key(key)
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idx = self.probe(key)
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slot = self.slots[idx]
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if slot is not self.empty and slot is not self.deleted and slot[0] == key:
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self.slots[idx] = self.deleted
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self._size -= 1
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else:
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raise KeyError(key)
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def __contains__(self, key):
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self._check_key(key)
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idx = self.probe(key)
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slot = self.slots[idx]
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return slot is not self.empty and slot is not self.deleted and slot[0] == key
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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 slot in self.slots:
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if slot is not self.empty and slot is not self.deleted:
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yield slot[0]
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