LeetCode 937 Reorder Log Files 解题报告

题目要求

You have an array of logs.  Each log is a space delimited string of words.

For each log, the first word in each log is an alphanumeric identifier.  Then, either:

• Each word after the identifier will consist only of lowercase letters, or;
• Each word after the identifier will consist only of digits.

We will call these two varieties of logs letter-logs and digit-logs.  It is guaranteed that each log has at least one word after its identifier.

Reorder the logs so that all of the letter-logs come before any digit-log.  The letter-logs are ordered lexicographically ignoring identifier, with the identifier used in case of ties.  The digit-logs should be put in their original order.

Return the final order of the logs.

题目分析及思路

给定一组字符串，每个字符串中的内容由空格隔开，且每个字符串开头是一个由数字和字母组成的标识符。之后要么全是数字（digit-logs），要么全是小写单词（letter-logs）。且保证标识符后一定会有内容。最后要求返回的结果是：letter-logs要在digit-logs前面，其中letter-logs要按字母表顺序排列（忽略标识符），digit-logs按原始顺序排列。可以遍历该数组，将标识符和后面的内容分开，将digit-logs按顺序放在单独的数组中，再对letter-logs进行排序。最后将两个列表组合。

python代码

class Solution:

    def reorderLogFiles(self, logs: List[str]) -> List[str]:

        final_logs = []

        digit_logs = []

        digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']

        for log in logs:

            idx = log.index(' ')

            if log[idx+1] in digits:

                digit_logs.append(log)

            else:

                final_logs.append(log)

                final_logs.sort(key = lambda l:l[l.index(' ')+1:])

        final_logs.extend(digit_logs)

        return final_logs