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85 lines
2.4 KiB
Python
85 lines
2.4 KiB
Python
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#!/usr/bin/env python3
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from number_theory.prime_numbers import next_prime
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class HashTable:
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"""
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Basic Hash Table example with open addressing and linear probing
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"""
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def __init__(self, size_table, charge_factor=None, lim_charge=None):
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self.size_table = size_table
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self.values = [None] * self.size_table
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self.lim_charge = 0.75 if lim_charge is None else lim_charge
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self.charge_factor = 1 if charge_factor is None else charge_factor
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self.__aux_list = []
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self._keys = {}
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def keys(self):
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return self._keys
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def balanced_factor(self):
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return sum([1 for slot in self.values
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if slot is not None]) / (self.size_table * self.charge_factor)
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def hash_function(self, key):
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return key % self.size_table
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def _step_by_step(self, step_ord):
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print("step {0}".format(step_ord))
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print([i for i in range(len(self.values))])
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print(self.values)
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def bulk_insert(self, values):
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i = 1
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self.__aux_list = values
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for value in values:
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self.insert_data(value)
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self._step_by_step(i)
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i += 1
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def _set_value(self, key, data):
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self.values[key] = data
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self._keys[key] = data
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def _colision_resolution(self, key, data=None):
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new_key = self.hash_function(key + 1)
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while self.values[new_key] is not None \
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and self.values[new_key] != key:
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if self.values.count(None) > 0:
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new_key = self.hash_function(new_key + 1)
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else:
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new_key = None
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break
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return new_key
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def rehashing(self):
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survivor_values = [value for value in self.values if value is not None]
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self.size_table = next_prime(self.size_table, factor=2)
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self._keys.clear()
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self.values = [None] * self.size_table #hell's pointers D: don't DRY ;/
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map(self.insert_data, survivor_values)
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def insert_data(self, data):
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key = self.hash_function(data)
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if self.values[key] is None:
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self._set_value(key, data)
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elif self.values[key] == data:
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pass
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else:
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colision_resolution = self._colision_resolution(key, data)
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if colision_resolution is not None:
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self._set_value(colision_resolution, data)
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else:
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self.rehashing()
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self.insert_data(data)
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