Print Number containing Digit only 1 2 3

Print Number containing Digit only 1 2 3

  January 24, 2018    

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Idea is to use REGEX.

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
class GFG
 {
     static boolean flag;
     static List<String> lst=new ArrayList<String>();
public static void checkExpr(String str)
{
Pattern p=Pattern.compile(".*[^123].*");
Matcher m=p.matcher(str);
if(!m.find())
{
     lst.add(str);
     flag=true;
}
}
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=ab.nextInt();
while(t-->0)
{
    int n=ab.nextInt();
    flag=false;
    lst.clear();
    for(int i=0;i<n;++i)
    checkExpr(ab.next());
    Collections.sort(lst);
    for(String s:lst)
    System.out.print(s+" ");
    if(!flag)
    System.out.print("-1");
    System.out.println();
}
}
}