Logger System with Handler Pipeline and Keyword Search

Problem: Implement a Logger System with Handler Pipeline and Keyword Search Design and implement a simplified Logger System. The system should support the following features: Add handlers Handlers form a pipeline in the order they are added. Every newly written log is processed by all currently registered handlers in order. Existing logs are not reprocessed when a new handler is added later. Write logs Write a raw log message. The system processes it through all current handlers and stores the processed message. Each stored log receives an incremental log_id starting from 0. Search keyword Given a keyword, return all log_ids whose processed log contains that keyword, in increasing order. Search rules: Match complete words only. A word consists of English letters or digits, i.e. regex [A-Za-z0-9]+. Search is case-insensitive. Search should be optimized: do not scan all logs on every search. Maintain an inverted index when logs are added. This problem supports two handler types: CAPITAL: converts the whole current log message to uppercase. ADD suffix: appends suffix to the end of the current log message. Input Format The first line contains an integer Q, the number of operations. Each of the next Q lines is one of the following operations: ADD_HANDLER CAPITAL ADD_HANDLER ADD <suffix> LOG <message> SEARCH <keyword> Notes: <message> and <suffix> may contain any characters except newline. <keyword> is a word containing only English letters or digits. Output Format For each SEARCH operation: If matching logs exist, print all matching log_ids separated by a single space. Otherwise, print EMPTY. Constraints 1 <= Q <= 2 * 10^5 Length of each message/suffix <= 10^3 Total number of characters after all LOG operations <= 10^6 Expected complexity: LOG should be close to the length of the current processed message. SEARCH should be close to the number of returned results, not the number of all logs. Example Input: 5 LOG hello world SEARCH hello ADD_HANDLER CAPITAL LOG hello world SEARCH hello Output: 0 0 1 Example Input 5 LOG hello world SEARCH hello ADD_HANDLER CAPITAL LOG hello world SEARCH hello Output 0 0 1