def makeEmpty(self):
tempIndex = 0
while tempIndex < len(self.buckets):
self.buckets[tempIndex] = MapEntry()
tempIndex += 1
self.currentSize = 0
return
def __init__(self,
keyComparator: Comparator = None,
valueComparator: Comparator = None,
size: int = 10):
"""
:type keyComparator: object
:type valueComparator: object
:type size: int
"""
self.buckets = [MapEntry()] * size
self.currentSize = 0
self.keyComparator = keyComparator
self.valueComparator = valueComparator
def put(self, key, value) -> bool:
# We first create the object to be added into the table and initialize final index position
newEntry = MapEntry(key, value, True)
# We first check if it exists on the the table
# OPTIONAL - IF DESIRED WE CAN RESTRICT THE LIST TO ONLY
# ACCEPT ELEMENTS THAT ARE NOT ALREADY IN HASH TABLE
if self.containsKey(key):
self.remove(key)
# Check if percentage of elements is below 50% of capacity
if (self.currentSize / len(self.buckets)) >= 0.5:
# if its over half capacity, extend array (WORST CASE SCENARIO)
self.__reallocate()
# ---------------------------------------
# We begin by first locating first hashing position
firstFreePosition = self.linearHashFunction(key, self.buckets)
entryIndex = firstFreePosition
if self.buckets[entryIndex] is not None and self.buckets[
entryIndex].isStatus() is not False:
# ---------------------------------------
# If first hashing position fails we proceed to second hash
secondFreePosition = self.squareHashFunction(key, self.buckets)
entryIndex = secondFreePosition
if self.buckets[entryIndex] is not None and self.buckets[
entryIndex].isStatus() is not False:
# ---------------------------------------
# If second hashing position fails we proceed to second hash
thirdFreePosition = self.cubicHashFunction(key, self.buckets)
entryIndex = thirdFreePosition
if self.buckets[entryIndex] is not None and self.buckets[
entryIndex].isStatus() is not False:
# ---------------------------------------
# If third hash fails we proceed to linear probing
tempIndex = (self.linearHashFunction(key, self.buckets) +
1) % len(self.buckets)
while tempIndex != self.linearHashFunction(
key, self.buckets):
# If empty space is found then set index to such spot
if self.buckets[tempIndex] is not None and self.buckets[
tempIndex].isStatus() is False:
entryIndex = tempIndex
break
tempIndex = (tempIndex + 1) % len(self.buckets)
self.buckets[entryIndex] = newEntry
self.currentSize += 1
return True
def put(self, key, value):
# Creation of new element to be included in Hash Table
newEntry = MapEntry(key, value, True)
# Check if element doesn't exist
if self.containsKey(key) is True:
# if it does exist delete
self.remove(key)
# We check if the existing ratio between elements and spaces hasn't surpassed 70%
if self.size() / len(self.buckets) >= 0.7:
# if surpassed reAllocate the hash table
self.__reAllocate()
# To know corresponding location, we hash it first
firstElementPosition = self.linearHashFunction(key, self.buckets)
firstList = self.buckets[firstElementPosition]
# We add it to the list
firstList.add(newEntry)
self.currentSize += 1
return True
def remove(self, key) -> object:
# We begin search of the element with first hash functions
firstPosition = self.linearHashFunction(key, self.buckets)
eliminateIndex = firstPosition
firstElement = self.buckets[firstPosition]
if firstElement.isStatus() is False or firstElement.getKey(
) is not key:
# If first hashing fails proceed to second hashing
secondPosition = self.squareHashFunction(key, self.buckets)
secondElement = self.buckets[secondPosition]
eliminateIndex = secondPosition
if secondElement.isStatus() is False or secondElement.getKey(
) is not key:
# If first hashing fails proceed to second hashing
thirdPosition = self.cubicHashFunction(key, self.buckets)
thirdElement = self.buckets[thirdPosition]
eliminateIndex = thirdPosition
if thirdElement.isStatus() is False or thirdElement.getKey(
) is not key:
# If third hashing fails we proceed into linear probing
tempIndex = (self.linearHashFunction(key, self.buckets) +
1) % len(self.buckets)
while tempIndex != self.linearHashFunction(
key, self.buckets):
# If specified loc
if self.buckets[tempIndex].isStatus(
) is True and self.buckets[tempIndex].getKey() is key:
eliminateIndex = tempIndex
break
tempIndex = (tempIndex + 1) % len(self.buckets)
# if linear probe fails the object doesn't exist
if self.linearHashFunction(key, self.buckets) == tempIndex:
return None
result = self.buckets[eliminateIndex].getValue()
self.buckets[eliminateIndex] = MapEntry()
self.currentSize -= 1
return result