masking-personal-information.py

# Time:  O(1)
# Space: O(1)

# We are given a personal information string S,
# which may represent either an email address or a phone number.
#
# We would like to mask this personal information according to the following
# rules:
#
# 1. Email address:
# We define a name to be a string of length ≥ 2 consisting of only lowercase
# letters a-z or uppercase letters A-Z.
# An email address starts with a name, followed by the symbol '@', followed by
# a name, followed by the dot '.' and followed by a name.
# All email addresses are guaranteed to be valid and in the format of
# "name1@name2.name3".
# To mask an email, all names must be converted to lowercase and all letters
# between the first and last letter of the first name must be replaced by
# 5 asterisks '*'.
#
# 2. Phone number:
# A phone number is a string consisting of only the digits 0-9 or the
# characters from the set {'+', '-', '(', ')', ' '}. You may assume
# a phone number contains 10 to 13 digits.
# The last 10 digits make up the local number, while the digits before those
# make up the country code. Note that the country code is optional. We want to
# expose only the last 4 digits and mask all other digits.
# The local number should be formatted and masked as "***-***-1111",
# where 1 represents the exposed digits.
# To mask a phone number with country code like "+111 111 111 1111",
# we write it in the form "+***-***-***-1111".  The '+' sign and the first '-'
# sign before the local number should only exist if there is a country code.
# For example, a 12 digit phone number mask should start with "+**-".
#
# Note that extraneous characters like "(", ")", " ", as well as extra dashes
# or plus signs not part of the above formatting scheme should be removed.
#
# Return the correct "mask" of the information provided.
#
# Example 1:
#
# Input: "LeetCode@LeetCode.com"
# Output: "l*****e@leetcode.com"
# Explanation: All names are converted to lowercase, and the letters between
# the first and last letter of the first name is replaced by 5 asterisks.
#              Therefore, "leetcode" -> "l*****e".
# Example 2:
#
# Input: "AB@qq.com"
# Output: "a*****b@qq.com"
# Explanation: There must be 5 asterisks between the first and last letter
#              of the first name "ab". Therefore, "ab" -> "a*****b".
# Example 3:
#
# Input: "1(234)567-890"
# Output: "***-***-7890"
# Explanation: 10 digits in the phone number, which means all digits make up
# the local number.
# Example 4:
#
# Input: "86-(10)12345678"
# Output: "+**-***-***-5678"
# Explanation: 12 digits, 2 digits for country code and 10 digits for local
# number.
# Notes:
#
# S.length <= 40.
# Emails have length at least 8.
# Phone numbers have length at least 10.


class Solution(object):
    def maskPII(self, S):
        """
        :type S: str
        :rtype: str
        """
        if '@' in S:
            first, after = S.split('@')
            return "{}*****{}@{}".format(first[0], first[-1], after).lower()

        digits = filter(lambda x: x.isdigit(), S)
        local = "***-***-{}".format(digits[-4:])
        if len(digits) == 10:
            return local
        return "+{}-{}".format('*' * (len(digits) - 10), local)