We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
  1. Prepare
  2. Regex
  3. Assertions
  4. Negative Lookahead
  5. Discussions

Negative Lookahead

  • preethiannjacob
     + 0 comments

    Java 15

    import java.io.*;
import java.util.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class Solution {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Pattern pattern = Pattern.compile("(.)(?!\\1)"); 
        // "\\1" is a backreference to the first captured group. It is a backreference which will be translated into the same character found in (.), whatever character that is.
        // Note: Does not work without parenthesis: ".(?!\\1)"
        Matcher matcher = pattern.matcher(scanner.next());
        int count=0;
        while(matcher.find()) count++;
        System.out.println("Number of matches : "+count);
    }
}