Group Logs by User and Sort by Timestamp

You are given a list of log entries. Each log entry contains three fields: a positive integer user_id, a non-negative integer timestamp (representing the Unix timestamp), and a non-empty string action describing the user action.

Your task is to group the logs by user_id and, for each user, sort the corresponding actions in ascending order of their timestamp. Then, print the results in ascending order of the user IDs. The output for each user must be on a separate line in the following format:

user_id: action1 action2 ... actionK

It is guaranteed that the input data follows the constraints.

Note: If there are no log entries, the program should produce no output.

Mathematical formulation:

Let \(L = [l_1, l_2, \ldots, l_n]\) be a list of logs where each log \(l_i\) is a tuple \((u_i, t_i, a_i)\). For each unique user id \(u\), output the sorted list of actions \(A(u) = [a_{i_1}, a_{i_2}, \ldots, a_{i_k}]\) such that \(t_{i_1} \le t_{i_2} \le \ldots \le t_{i_k}\).

inputFormat

The input is read from standard input (stdin) and is formatted as follows:

• The first line contains a single integer n representing the number of log entries.
• The next n lines each contain a log entry in the format: user_id timestamp action

Constraints:

• user_id is a positive integer.
• timestamp is a non-negative integer.
• action is a non-empty string (it will not contain whitespace).

outputFormat

For each distinct user_id, output a line containing the user_id followed by a colon and the list of actions (sorted in ascending order by timestamp) separated by a space. The users should be printed in ascending order of their user_id. If there are no logs, output nothing.

## sample

5
1 1622476800 login
2 1622476860 view_page
1 1622476900 logout
1 1622476805 click_button
2 1622476890 logout

1: login click_button logout
2: view_page logout

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