Reorder Data in Log Files — LeetCode 937 Python Solution

The problem

You are given an array of logs. Each log is a space-delimited string of words, where the first word is the identifier.

Example

Input

logs = ["dig1 8 1 5 1","let1 art can","dig2 3 6","let2 own kit dig","let3 art zero"]

Output

["let1 art can","let3 art zero","let2 own kit dig","dig1 8 1 5 1","dig2 3 6"]

Explanation

The letter-log contents are all different, so their ordering is "art can", "art zero", "own kit dig".

Python solution

class Solution:
    def reorderLogFiles(self, logs: List[str]) -> List[str]:
        def f(log: str):
            id_, rest = log.split(" ", 1)
            return (0, rest, id_) if rest[0].isalpha() else (1,)

        return sorted(logs, key=f)

Complexity

Pattern: Sorting

Spend O(n log n) once to buy an ordering that makes the rest of the problem trivial. LeetCode 937. Reorder Data in Log Files is filed here because LeetCode tags it Sorting, which is the vocabulary this hub collects.

The sorting guide has the Python template for the pattern and the 401 LeetCode problems that use it.

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