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  1. Prepare
  2. Regex
  3. Assertions
  4. Negative Lookahead
  5. Discussions

Negative Lookahead

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38 Discussions

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  • sz_csaba
     + 0 comments

    This problem does not support named backreferences

  • 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);
    }
}

  • brantes
     + 0 comments

    (.)(?!\1)

  • 21A31A05J1
     + 0 comments

    see my regex

    r"(.)(?!\1)"

  • Tania15
     + 0 comments

    Regex_Pattern = r"(.)(?!\1)" # Do not delete 'r'.

    import re

    Test_String = input()

    match = re.findall(Regex_Pattern, Test_String)

    print("Number of