g0801_0900.s0831_masking_personal_information.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated
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package g0801_0900.s0831_masking_personal_information;

// #Medium #String #2022_03_24_Time_1_ms_(84.30%)_Space_42.1_MB_(63.64%)

/**
 * 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 = "[email protected]"
 *
 * **Output:** "l\*\*\*\*\*[email protected]"
 *
 * **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 = "[email protected]"
 *
 * **Output:** "a\*\*\*\*\*[email protected]"
 *
 * **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 `'+'`.
**/
public class Solution {
    public String maskPII(String s) {
        StringBuilder masked = new StringBuilder();
        if (Character.isAlphabetic(s.charAt(0))) {
            int locationOfAtSymbol = s.indexOf("@") - 1;
            masked.append(s.charAt(0)).append("*****").append(s.substring(locationOfAtSymbol));
            return masked.toString().toLowerCase();
        } else {
            StringBuilder allDigits = new StringBuilder();
            int pointer = -1;
            while (++pointer < s.length()) {
                if (Character.isDigit(s.charAt(pointer))) {
                    allDigits.append(s.charAt(pointer));
                }
            }
            int 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));
            return masked.toString();
        }
    }
}