Stream String Checker

Implement a program to process an input stream. Each input is in the format of [timestamp, string], and the program needs to output all unique strings within the last 60 seconds. If a duplicate string is found, the current string should be dropped and not appear in the output. The follow-up requires dropping all duplicates within the last 60 seconds once a duplicate is found. Specific requirements are as follows: Each input is an array in the format of [timestamp, string]. timestamp is an integer representing time in seconds. In the output, return all strings without duplicates from the last 60 seconds. If a certain input lists a string that has appeared within the last 60 seconds, the string from this input is dropped. In the follow-up handling requirement, if an input string appears again, all duplicate strings within 60 seconds should be dropped. Example: Suppose the input stream is: [0, 'a'] [30, 'b'] [60, 'a'] [61, 'c'] [120, 'a'] The output will be: ['a', 'b', 'c'] When 'a' appears the second time, since it reappears within the past 60 seconds, it is dropped. Can this program handle these requirements correctly? Example Input 0 a 30 b 60 a 61 c 120 a