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All remaining methods implemented

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Andrew Scott 2022-06-02 22:35:31 -04:00
parent 1dba75f273
commit 0cccf1873c
Signed by: a
GPG key ID: 3EB62D0BBB8DB381
1 changed files with 44 additions and 20 deletions
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64
hash_map_oa.py
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@ -62,14 +62,10 @@ class HashMap:
Value to add, or update if the key is already present Value to add, or update if the key is already present
""" """
# remember, if the load factor is greater than or equal to 0.5, # resize if necessary
# resize the table before putting the new key/value pair
if self.table_load() >= 0.5: if self.table_load() >= 0.5:
self.resize_table(self._capacity * 2) self.resize_table(self._capacity * 2)
# calculate proper index and add/update HashEntry
hash = self._hash_function(key) hash = self._hash_function(key)
initial_index = hash % self._capacity initial_index = hash % self._capacity
is_placed = False is_placed = False
@ -84,6 +80,7 @@ class HashMap:
self._buckets[index].key = key self._buckets[index].key = key
self._buckets[index].value = value self._buckets[index].value = value
self._buckets[index].is_tombstone = False self._buckets[index].is_tombstone = False
self._size += 1
is_placed = True is_placed = True
elif self._buckets[index].key == key: elif self._buckets[index].key == key:
self._buckets[index].value = value self._buckets[index].value = value
@ -119,7 +116,6 @@ class HashMap:
count += 1 count += 1
return count return count
def resize_table(self, new_capacity: int) -> None: def resize_table(self, new_capacity: int) -> None:
"""Changes the capacity of the hash table """Changes the capacity of the hash table
@ -132,7 +128,7 @@ class HashMap:
New capacity for the hash table New capacity for the hash table
""" """
# immediately return if new_capacity is less than 1 # immediately return if new_capacity is invalid
if new_capacity < 1 or new_capacity < self._size: if new_capacity < 1 or new_capacity < self._size:
return return
# create new hash table # create new hash table
@ -161,9 +157,19 @@ class HashMap:
The value associated with the key if it exists, otherwise None The value associated with the key if it exists, otherwise None
""" """
for i in range(self._capacity): hash = self._hash_function(key)
if self._buckets[i] is not None and self._buckets[i].key == key: initial_index = hash % self._capacity
return self._buckets[i].value index = initial_index
quadratic_factor = 0
while self._buckets[index] is not None:
if (
self._buckets[index].key == key
and not self._buckets[index].is_tombstone
):
return self._buckets[index].value
else:
quadratic_factor += 1
index = (initial_index + quadratic_factor**2) % self._capacity
return None return None
def contains_key(self, key: str) -> bool: def contains_key(self, key: str) -> bool:
@ -180,9 +186,16 @@ class HashMap:
True if the key is in the hash map, otherwise False True if the key is in the hash map, otherwise False
""" """
for i in range(self._capacity): hash = self._hash_function(key)
if self._buckets[i] is not None and self._buckets[i].key == key: initial_index = hash % self._capacity
index = initial_index
quadratic_factor = 0
while self._buckets[index] is not None:
if self._buckets[index].key == key:
return True return True
else:
quadratic_factor += 1
index = (initial_index + quadratic_factor**2) % self._capacity
return False return False
def remove(self, key: str) -> None: def remove(self, key: str) -> None:
@ -194,10 +207,21 @@ class HashMap:
Key to look up in the hash map Key to look up in the hash map
""" """
for i in range(self._capacity): hash = self._hash_function(key)
if self._buckets[i] is not None and self._buckets[i].key == key: initial_index = hash % self._capacity
self._buckets[i].is_tombstone = True index = initial_index
quadratic_factor = 0
while self._buckets[index] is not None:
if (
self._buckets[index].key == key
and not self._buckets[index].is_tombstone
):
self._buckets[index].is_tombstone = True
self._size -= 1 self._size -= 1
return
else:
quadratic_factor += 1
index = (initial_index + quadratic_factor**2) % self._capacity
def clear(self) -> None: def clear(self) -> None:
""" """
@ -206,8 +230,7 @@ class HashMap:
self._buckets = DynamicArray() self._buckets = DynamicArray()
self._size = 0 self._size = 0
self._capacity = self._buckets.length() for i in range(self._capacity):
for i in range(self._buckets.length()):
self._buckets.append(None) self._buckets.append(None)
def get_keys(self) -> DynamicArray: def get_keys(self) -> DynamicArray:
@ -219,10 +242,11 @@ class HashMap:
Array containing the hash maps keys Array containing the hash maps keys
""" """
keys = DynamicArray keys = DynamicArray()
for i in range(self._capacity): for i in range(self._capacity):
if self._buckets[i] is not None: if self._buckets[i] is not None and not self._buckets[i].is_tombstone:
keys.append(self._buckets[i].key) keys.append(self._buckets[i].key)
return keys
# ------------------- BASIC TESTING ---------------------------------------- # # ------------------- BASIC TESTING ---------------------------------------- #