hash functions added

data_structures/hashing/double_hash.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+
+from .hash_table import HashTable
+from number_theory.prime_numbers import next_prime, check_prime
+
+
+class DoubleHash(HashTable):
+    """
+        Hash Table example with open addressing and Double Hash
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    def __hash_function_2(self, value, data):
+
+        next_prime_gt = next_prime(value % self.size_table) \
+            if not check_prime(value % self.size_table) else value % self.size_table  #gt = bigger than
+        return next_prime_gt - (data % next_prime_gt)
+
+    def __hash_double_function(self, key, data, increment):
+        return (increment * self.__hash_function_2(key, data)) % self.size_table
+
+    def _colision_resolution(self, key, data=None):
+        i = 1
+        new_key = self.hash_function(data)
+
+        while self.values[new_key] is not None and self.values[new_key] != key:
+            new_key = self.__hash_double_function(key, data, i) if \
+                self.balanced_factor() >= self.lim_charge else None
+            if new_key is None: break 
+            else: i += 1
+
+        return new_key