Code Sprint 2 - Fraud Prevention

gistfile1.py

#!/usr/bin/env python

import re

def normalise_email(email):
    email = email.lower()
    i = email.find("@")
    prefix = email[:i]
    j = prefix.find("+")
    if j != -1:
        prefix = prefix[:j]
    prefix = prefix.replace(".", "")
    return prefix + email[i:]

def normalise_address(street, city, state, code):
    street = street.strip().lower()
    street = re.sub("\s+", " ", street)
    street = re.sub(" (street|st.)$", " st", street)
    street = re.sub(" (road|rd.)$", " rd", street)
    city = city.strip().lower()
    city = re.sub("\s+", " ", city)
    state = state.strip().lower()
    if state == 'california': state = 'ca'
    if state == 'illinois': state = 'il'
    if state == 'new york': state = 'ny'
    code = code.strip()
    return "%s,%s,%s,%s" % (street, city, state, code)

def process(oid, did, key, cc, stash, orders):
    # For each combination of the deal id and the key we are going to keep
    # a tuple of the CC and a set of order ids where it was used.
    stash_key = str(did) + "," + key
    if stash_key not in stash:
        stash[stash_key] = (cc, set([oid]))
    else:
        # The deal,key combination has been seen before.
        prev_cc, oid_set = stash[stash_key]
        if cc != prev_cc:
            # New CC number, mark the current as the previous orders as fraudulent.
            orders.add(oid)
            orders.update(oid_set)
            # Clear the set of orders so that all future orders are marked as
            # fraudulent, regardless of their CC.
            oid_set.clear()
        else:
            if oid_set:
                # Same CC, save the order in case we need to mark all of them as
                # fraudulent.
                oid_set.add(oid)
            else:
                # Even though the CC is the same, there was a fraudulent order
                # for this key in the past, have to mark this one too.
                orders.add(oid)

def main():
    emails = {}
    addresses = {}
    orders = set()

    N = input()
    for n in xrange(N):
        oid, did, email, street, city, state, code, cc = raw_input().split(",")
        oid, did = int(oid), int(did)
        email = normalise_email(email)
        address = normalise_address(street, city, state, code)
        process(oid, did, email, cc, emails, orders)
        process(oid, did, address, cc, addresses, orders)

    print ",".join([str(i) for i in sorted(orders)])
        
if __name__ == "__main__":
    main()