What is the method to write the following regular expression avoiding catastrophic backtracking?

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Without knowing the specific regular expression causing catastrophic backtracking, it is impossible to provide a specific method to avoid it. However, there are some general tips to reduce the risk of catastrophic backtracking:

1. Use more specific and restrictive quantifiers instead of the wildcard character (.). For example, instead of using ".*" to match any character, use "[a-zA-Z]+" to match one or more alphabetic characters.

2. Avoid nested quantifiers, which can cause exponential processing time. For example, avoid using "(a.b)" to match any number of strings containing the characters 'a' and 'b', as this can cause catastrophic backtracking for longer strings.

3. Use lookarounds to reduce backtracking. For example, use positive lookaheads to ensure that a pattern exists ahead, before actually trying to match it. This can help avoid unnecessary backtracking.

4. Use atomic groups and possessive quantifiers to make the regex engine "commit" to a match as soon as possible, instead of backtracking. This can be particularly useful when dealing with long strings or patterns with multiple alternations.

Overall, the best approach to avoid catastrophic backtracking is to carefully design and test regular expressions, and during testing, make sure to apply them to realistic inputs of varying lengths and complexity.