Yang W. answered • 04/15/24
Tutor
5
(16)
Data Scientist with 7+ Years of Experience in Python & R
#!/usr/bin/env python3
from typing import List
def binary_search(valid_accounts: List[int], account_number: int) -> bool:
left = 0
right = len(valid_accounts) - 1
while left <= right:
# Floor division to handle both odd and even array length
middle = (left + right) // 2
# If valid, return True
if account_number == valid_accounts[middle]:
return True
# This means that the account number is left of the mid-point
if account_number < valid_accounts[middle]:
# Move the right pointer towards the left
right = middle - 1
# This means that the account number is right of the mid-point
elif account_number > valid_accounts[middle]:
# Move the left pointer towards the right
left = middle + 1
# Not found
return False
def main() -> int:
# Sorted accounts
valid_accounts = [
1750219, 2419590, 2545408, 2931356, 3080098, 3164838,
4282637, 4449539, 4578589, 5104726, 5333174, 6086650,
6749941, 6755963, 8149420, 9387197, 9526981, 9718904
]
# Validation
while True:
try:
account_number = input("Please enter a (7 digits) account number as a series of integers (no quotes): ")
if not account_number.isdigit() or len(account_number) != 7:
raise ValueError("Unable to verify; the account number must be a 7-digit integer")
break
except ValueError as e:
print(e)
found = binary_search(valid_accounts=valid_accounts, account_number=int(account_number))
message = f"The account number '{account_number}' is"
print(f"{message} {'valid' if found else 'invalid'}")
return 0
if __name__ == "__main__":
main()
