import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
public class Main {
    public static void main(String[] args) {
        String p1 = "(?:[0-9a-f]{1,4}:|::){1,15}(?:[0-9a-f]{1,4})?";
        String p2 = "(?:[0-9a-f]{1,4})?(?::[0-9a-f]{1,4}|::){1,14}(?:[0-9a-f]{1,4})?";
        String pp = "^"+p2+"$";
        System.out.println(pp);
        var p = Pattern.compile(pp);
        List<String> lists = new ArrayList<>();
        lists.add("2600:1500:5aa0:30ce:678f:520a:7875:a690");
        lists.add("2600:1500:5aa0:30ce::1");
        lists.add("2001:db8::1");
        lists.add("fe80::9871:44ae:e337:359a");
        lists.add("::1");
        for(String str : lists) {
            var m = p.matcher(str);
            var found = m.find();
            if(found) {
                System.out.println(str+" -> "+found+" "+m.group(0));
            } else {
                System.out.println(str + " -> " + found);
            }
        }
    }
}