Google Software Engineer interview questions

Hash Table related question, question was easy, but it required me to be quick and precise, first time optimal solution without wasting much time in discussing brute force, so that they can ask and implement a follow up question

You are given a structure struct LogMessage { string source; string message; }; Source is the filename and message is the log messages. There is a list of source(files) and log messages. You are given a limit of max log messages which you have to return on a fair basis. Example: { f1: "msg1", "msg2", "msg3","msg4" f2: "msgA", "msgB", "msgC", "msgD" f3: "msgX" } Suppose if max limit is given as 5, then from file 1, return 2 messages, file2 return 2 messages and file 3, return 1 message.