Design Log Storage System — LeetCode 635 Python Solution

The problem

You are given several logs, where each log contains a unique ID and timestamp. Timestamp is a string that has the following format: Year:Month:Day:Hour:Minute:Second, for example, 2017:01:01:23:59:59.

Example

Input

["LogSystem", "put", "put", "put", "retrieve", "retrieve"]

Output

[null, null, null, null, [3, 2, 1], [2, 1]]

Explanation

LogSystem logSystem = new LogSystem();

Python solution

class LogSystem:
    def __init__(self):
        self.logs = []
        self.d = {
            "Year": 4,
            "Month": 7,
            "Day": 10,
            "Hour": 13,
            "Minute": 16,
            "Second": 19,
        }

    def put(self, id: int, timestamp: str) -> None:
        self.logs.append((id, timestamp))

    def retrieve(self, start: str, end: str, granularity: str) -> List[int]:
        i = self.d[granularity]
        return [id for id, ts in self.logs if start[:i] <= ts[:i] <= end[:i]]


# Your LogSystem object will be instantiated and called as such:
# obj = LogSystem()
# obj.put(id,timestamp)
# param_2 = obj.retrieve(start,end,granularity)

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 635. Design Log Storage System is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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