LeetCode in Kotlin

831. Masking Personal Information

Medium

You are given a personal information string s, representing either an email address or a phone number. Return the masked personal information using the below rules.

Email address:

An email address is:

• A name consisting of uppercase and lowercase English letters, followed by
• The '@' symbol, followed by
• The domain consisting of uppercase and lowercase English letters with a dot '.' somewhere in the middle (not the first or last character).

To mask an email:

• The uppercase letters in the name and domain must be converted to lowercase letters.
• The middle letters of the name (i.e., all but the first and last letters) must be replaced by 5 asterisks "*****".

Phone number:

A phone number is formatted as follows:

• The phone number contains 10-13 digits.
• The last 10 digits make up the local number.
• The remaining 0-3 digits, in the beginning, make up the country code.
• Separation characters from the set {'+', '-', '(', ')', ' '} separate the above digits in some way.

To mask a phone number:

• Remove all separation characters.
• The masked phone number should have the form:
  • "***-***-XXXX" if the country code has 0 digits.
  • "+*-***-***-XXXX" if the country code has 1 digit.
  • "+**-***-***-XXXX" if the country code has 2 digits.
  • "+***-***-***-XXXX" if the country code has 3 digits.
• "XXXX" is the last 4 digits of the local number.

Example 1:

Input: s = “LeetCode@LeetCode.com”

Output: “l*****e@leetcode.com”

Explanation: s is an email address.

The name and domain are converted to lowercase, and the middle of the name is replaced by 5 asterisks.

Example 2:

Input: s = “AB@qq.com”

Output: “a*****b@qq.com”

Explanation: s is an email address.

The name and domain are converted to lowercase, and the middle of the name is replaced by 5 asterisks.

Note that even though “ab” is 2 characters, it still must have 5 asterisks in the middle.

Example 3:

Input: s = “1(234)567-890”

Output: “***-***-7890”

Explanation: s is a phone number.

There are 10 digits, so the local number is 10 digits and the country code is 0 digits.

Thus, the resulting masked number is “***-***-7890”.

Constraints:

• s is either a valid email or a phone number.
• If s is an email:
  • 8 <= s.length <= 40
  • s consists of uppercase and lowercase English letters and exactly one '@' symbol and '.' symbol.
• If s is a phone number:
  • 10 <= s.length <= 20
  • s consists of digits, spaces, and the symbols '(', ')', '-', and '+'.

Solution

class Solution {
    fun maskPII(s: String): String {
        val masked = StringBuilder()
        return if (Character.isAlphabetic(s[0].code)) {
            val locationOfAtSymbol = s.indexOf("@") - 1
            masked.append(s[0]).append("*****").append(s.substring(locationOfAtSymbol))
            masked.toString().lowercase()
        } else {
            val allDigits = StringBuilder()
            var pointer = -1
            while (++pointer < s.length) {
                if (Character.isDigit(s[pointer])) {
                    allDigits.append(s[pointer])
                }
            }
            val numDigits = allDigits.length
            if (numDigits == 11) {
                masked.append("+*-")
            } else if (numDigits == 12) {
                masked.append("+**-")
            } else if (numDigits == 13) {
                masked.append("+***-")
            }
            masked.append("***-***-").append(allDigits.substring(numDigits - 4))
            masked.toString()
        }
    }
}

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