def fraud_detect_merge(first_booth_voters, second_booth_voters):
"""This function takes a VoterList from two voting booths and returns a new
VoterList, the voters who cast a vote in both booths, and an integer, the
number of VoterName comparisons the function made. Both VoterLists are in
lexicographical order."""
fraud_list = VoterList()
count = 0
pos1 = 0
pos2 = 0
first_len = len(first_booth_voters)
second_len = len(second_booth_voters)
while pos1 < first_len and pos2 < second_len:
first = first_booth_voters[pos1]
second = second_booth_voters[pos2]
count += 1
if first == second:
fraud_list.append(second)
pos1 += 1
pos2 += 1
else:
count += 1
if first < second:
pos1 += 1
else:
pos2 += 1
return fraud_list, count
def fraud_detect_bin(first_booth_voters, second_booth_voters):
"""This function takes a VoterList from two voting booths and returns a new
VoterList, the voters who cast a vote in both booths, and an integer, the
number of VoterName comparisons the function made. The second VoterList is
in lexicographical order."""
fraud_list = VoterList()
count = 0
for voter in first_booth_voters:
lowerBound = 0
upperBound = len(second_booth_voters)
mid = (lowerBound + upperBound) // 2
while lowerBound < upperBound:
count += 1
if second_booth_voters[mid] < voter:
lowerBound = mid + 1
else:
upperBound = mid
mid = (lowerBound + upperBound) // 2
if mid < len(second_booth_voters):
count += 1
if second_booth_voters[mid] == voter:
fraud_list.append(voter)
return fraud_list, count
def fraud_detect_seq(first_booth_voters, second_booth_voters):
"""This function takes a VoterList from two voting booths and returns a new
VoterList, the voters who cast a vote in both booths, and an integer, the
number of VoterName comparisons the function made. The VoterLists are
un-ordered."""
fraud_list = VoterList()
count = 0
for voter1 in first_booth_voters:
for voter2 in second_booth_voters:
count += 1
if voter1 == voter2:
fraud_list.append(voter1)
break
return fraud_list, count
def fraud_detect_hash(first_booth_voters, second_booth_voters):
"""This function takes a VoterList from two voting booths and returns a new
VoterList, the voters who cast a vote in both booths, and an integer, the
number of VoterName comparisons the function made. This function should use
a VoterHashTable initialised to an appropreate size to represent a hash
table, use the defualt hash function for VoterNames as a hash function and
use chaining to resolve collisions."""
fraud_list = VoterList()
count = 0
table_cap = len(second_booth_voters) * 2
voter_hash = VoterHashTable(table_cap)
for voter in first_booth_voters:
voter_index = hash(voter) % table_cap
voter_hash[voter_index].append(voter)
for voters in second_booth_voters:
index = hash(voters) % table_cap
for voter in voter_hash[index]:
count += 1
if voters == voter:
fraud_list.append(voters)
break
return fraud_list, count
def internal_comparisons_test(self, test_file_location, fraud_detect):
first_booth_voters, second_booth_voters, fraud_voters = read_test_data(
test_file_location)
fraud_found, comparisons = fraud_detect(first_booth_voters,
second_booth_voters)
self.assertEqual(comparisons, VoterList.get_comparisons())
def setUp(self):
VoterList.reset_comparisons()
VoterHashTable.reset_hashes()
VoterHashTable.reset_memory_used()
def setUp(self):
"""This runs before each test case"""
VoterList.reset_comparisons()
def read_test_data(filename):
"""Reads a test data file and returns a triple containg first booth voters,
second booth voters and voters comitting fraud by voting in both booths."""
first_booth_voters = VoterList()
second_booth_voters = VoterList()
fraud_voters = VoterList()
with open(filename) as test_data_file:
#Read first booth voter names
current_line = _get_next_line(test_data_file)
first_booth_voters_size = int(current_line)
for _ in range(first_booth_voters_size):
current_line = _get_next_line(test_data_file)
first_booth_voters.append(VoterName(current_line))
#Read second booth voter names
current_line = _get_next_line(test_data_file)
second_booth_voters_size = int(current_line)
for _ in range(second_booth_voters_size):
current_line = _get_next_line(test_data_file)
second_booth_voters.append(VoterName(current_line))
#Read voter names that commited fraud
current_line = _get_next_line(test_data_file)
fraud_voters_size = int(current_line)
for _ in range(fraud_voters_size):
current_line = _get_next_line(test_data_file)
fraud_voters.append(VoterName(current_line))
return first_booth_voters, second_booth_voters, fraud_voters