189 lines
5.7 KiB
Python
189 lines
5.7 KiB
Python
|
'''
|
||
|
Problem Statement: Consider telephone book database of N clients. Make use of a hash table implementation to quickly look up client's telephone number. Make use of two collision handling techniques and compare them using number of comparisons required to find a set of telephone numbers.
|
||
|
|
||
|
Code from Data Structures and Algorithms (SPPU - Second Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-se-comp-content/DataStructuresAndAlgorithms/
|
||
|
'''
|
||
|
|
||
|
# BEGINNING OF CODE
|
||
|
class HashEntry:
|
||
|
# Blueprint for entry in hash table
|
||
|
def __init__(self):
|
||
|
# Initializing empty values
|
||
|
self.name = None
|
||
|
self.num = -1
|
||
|
|
||
|
def insert(self, name, num):
|
||
|
# Insert value
|
||
|
self.name = name
|
||
|
self.num = num
|
||
|
|
||
|
def collision(self):
|
||
|
# Handle collision
|
||
|
return self.name is not None
|
||
|
|
||
|
def hashOne(size, val):
|
||
|
# Calculate first hashing function
|
||
|
return val % size
|
||
|
|
||
|
def hashTwo(val):
|
||
|
# Calculate second hashing function
|
||
|
return 7 - (val % 7)
|
||
|
|
||
|
def finalHash(val, size, i):
|
||
|
# Determine final position of value in hash table (after first and second hash is caluclated)
|
||
|
return (hashOne(size, val) + i * hashTwo(val)) % size
|
||
|
|
||
|
def stringToInt(strn):
|
||
|
# ASCII value of each character
|
||
|
sum = 0
|
||
|
for i in strn:
|
||
|
sum += ord(i)
|
||
|
return sum
|
||
|
|
||
|
class LinearProbing:
|
||
|
# Function to handle linear probing
|
||
|
def __init__(self, size):
|
||
|
self.size = size
|
||
|
self.HashTable = []
|
||
|
for _ in range(size):
|
||
|
self.HashTable.append(HashEntry())
|
||
|
|
||
|
def insert(self):
|
||
|
inputStr = input("Enter telephone NUMBER and NAME of client (separated by space):\t")
|
||
|
inputVal = inputStr.split()
|
||
|
|
||
|
if len(inputVal) != 2:
|
||
|
print("\n==========\nPlease enter both telephone number and name.\n==========")
|
||
|
return
|
||
|
|
||
|
num, name = inputVal
|
||
|
name2 = stringToInt(name)
|
||
|
pos = hashOne(self.size, name2)
|
||
|
|
||
|
i = 1
|
||
|
while self.HashTable[pos].collision():
|
||
|
pos = (pos + i) % self.size
|
||
|
i += 1
|
||
|
self.HashTable[pos].insert(name, num)
|
||
|
print("\n==========\nInserted\n==========")
|
||
|
|
||
|
def search(self):
|
||
|
name = input("Enter name of the client:\t")
|
||
|
name2 = stringToInt(name)
|
||
|
pos = hashOne(self.size, name2)
|
||
|
|
||
|
i = 1
|
||
|
while self.HashTable[pos].name != name:
|
||
|
pos = (pos + i) % self.size
|
||
|
i += 1
|
||
|
if i == self.size + 1:
|
||
|
break
|
||
|
else:
|
||
|
print("\n==========\nTelephone number of the client", name, "is", self.HashTable[pos].num, "\n==========")
|
||
|
return
|
||
|
print("\n==========\nClient not found.\n==========")
|
||
|
|
||
|
def display(self):
|
||
|
j = 0
|
||
|
print("Pos", "Name", "Value", sep="\t|\t")
|
||
|
print("-----", "-----", "-----", sep="\t+\t")
|
||
|
for i in self.HashTable:
|
||
|
print(j, i.name, i.num, sep="\t|\t")
|
||
|
j += 1
|
||
|
|
||
|
class DoubleHashing:
|
||
|
# Function to handle double hashing
|
||
|
def __init__(self, size):
|
||
|
self.size = size
|
||
|
self.HashTable = []
|
||
|
for _ in range(size):
|
||
|
self.HashTable.append(HashEntry())
|
||
|
|
||
|
def insert(self):
|
||
|
inputStr = input("Enter telephone NUMBER and NAME of client (separated by space):\t")
|
||
|
inputVal = inputStr.split()
|
||
|
|
||
|
if len(inputVal) != 2:
|
||
|
print("\n==========\nPlease enter both telephone number and name.\n==========")
|
||
|
return
|
||
|
|
||
|
num, name = inputVal
|
||
|
name2 = stringToInt(name)
|
||
|
|
||
|
i = 0
|
||
|
while True:
|
||
|
pos = finalHash(name2, self.size, i)
|
||
|
if self.HashTable[pos].collision():
|
||
|
i += 1
|
||
|
else:
|
||
|
break
|
||
|
self.HashTable[pos].insert(name, num)
|
||
|
print("\n==========\nInserted\n==========")
|
||
|
|
||
|
def search(self):
|
||
|
name = input("Enter name of the client:\t")
|
||
|
name2 = stringToInt(name)
|
||
|
i = 0
|
||
|
while True:
|
||
|
pos = finalHash(name2, self.size, i)
|
||
|
if self.HashTable[pos].name != name:
|
||
|
i += 1
|
||
|
else:
|
||
|
break
|
||
|
if i == self.size:
|
||
|
break
|
||
|
print("\n==========\nTelephone number of client", name, "is", self.HashTable[pos].num, "\n==========")
|
||
|
|
||
|
def display(self):
|
||
|
j = 0
|
||
|
print("Pos", "Name", "Value", sep="\t|\t")
|
||
|
print("-----", "-----", "-----", sep="\t+\t")
|
||
|
for i in self.HashTable:
|
||
|
print(j, i.name, i.num, sep="\t|\t")
|
||
|
j += 1
|
||
|
|
||
|
def main():
|
||
|
# Main function with options
|
||
|
tableSize = int(input("Enter size of hash table:\t"))
|
||
|
method = None
|
||
|
|
||
|
while True:
|
||
|
print("----- MAIN MENU -----")
|
||
|
print("1 -> Linear Probing")
|
||
|
print("2 -> Double Hashing")
|
||
|
print("3 -> Exit")
|
||
|
optn = int(input("Choose an option (1-3):\t"))
|
||
|
if optn == 1:
|
||
|
method = LinearProbing(tableSize)
|
||
|
elif optn == 2:
|
||
|
method = DoubleHashing(tableSize)
|
||
|
elif optn == 3:
|
||
|
print("\n\n## END OF CODE\n")
|
||
|
exit(1)
|
||
|
else:
|
||
|
print("Please choose a valid option (1-3).")
|
||
|
continue
|
||
|
|
||
|
while True:
|
||
|
print("\n----- CHOOSE OPERATION (HASH TABLE) -----")
|
||
|
print("1 -> Insert")
|
||
|
print("2 -> Search")
|
||
|
print("3 -> Display")
|
||
|
print("4 -> Return to previous menu")
|
||
|
optn = int(input("Choose an option (1-4):\t"))
|
||
|
if optn == 1:
|
||
|
method.insert()
|
||
|
elif optn == 2:
|
||
|
method.search()
|
||
|
elif optn == 3:
|
||
|
method.display()
|
||
|
elif optn == 4:
|
||
|
break
|
||
|
else:
|
||
|
print("Please choose a valid option (1-4).")
|
||
|
continue
|
||
|
|
||
|
# Calling main function
|
||
|
main()
|
||
|
# END OF CODE
|