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HW-02-git-and-java-practice/src/main/java/BonusExercises.java
T

107 lines
3.1 KiB
Java

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class BonusExercises {
/*
complete the method below, so it will validate an email address
1. Must have exactly one @ (no more, no less)
2. Split into local-part and domain (before @ and after @)
3. Local-part rules:
- Can't be empty
- Can't start or end with dot
- Can't have two dots in a row
4. Domain rules:
- Can't be empty
- Can't start or end with hyphen
- Can't have underscores
- Each segment (between dots) must follow same hyphen rules
*/
public boolean validateEmail(String email) {
String regex = ""; // todo
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(email);
return matcher.matches();
}
/*
This method should find and return the first date in a string.
Supported formats:
- American: MM/DD/YYYY (e.g., 12/09/2023)
- British: DD/MM/YYYY (e.g., 12/09/2023 — same pattern, context matters)
- ISO: YYYY-MM-DD (e.g., 2024-07-15)
- Slash variant: YYYY/MM/DD (e.g., 2025/01/01)
If no match for a date is found in the string, return null.
*/
public String findDate(String string) {
// todo
return null;
}
/*
given a string, implement the method to detect all valid passwords
then, it should return the count of them
a valid password has the following properties:
- at least 8 characters
- has to include at least one uppercase letter, and at least a lowercase
- at least one number and at least a special char "!@#$%^&*"
- has no white-space in it
*/
public int findValidPasswords(String string) {
// todo
return -1;
}
/*
you should return a list of *words* which are palindromic
by word we mean at least 3 letters with no whitespace in it
note: your implementation should be case-insensitive, e.g. Aba -> is palindrome
*/
public List<String> findPalindromes(String string) {
List<String> result = new ArrayList<>();
String[] words = string.split("\\s+");
for (int i = 0; i < words.length; i++) {
String word = words[i];
word = word.replaceAll("[^a-zA-Z]", "");
if (word.length() < 3) {
continue;
}
String lower = word.toLowerCase();
int left = 0;
int right = lower.length() - 1;
boolean isPalindrome = true;
while (left < right) {
if (lower.charAt(left) != lower.charAt(right)) {
isPalindrome = false;
break;
}
left++;
right--;
}
if (isPalindrome) {
result.add(word);
}
}
return result;
}
public static void main(String[] args) {
// you can test your code here
}
}