作者： 負雪明燭
id： fuxuemingzhu
個人部落格： http://fuxuemingzhu.cn/

目錄

• 題目描述
• 題目大意
• 解題方法
• 分割和排序
• 日期

題目地址：https://leetcode.com/problems/max-points-on-a-line/description/

題目描述

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.

Example 1:

Input: ["a1 9 2 3 1","g1 act car","zo4 4 7","ab1 off key dog","a8 act zoo"]
Output: ["g1 act car","a8 act zoo","ab1 off key dog","a1 9 2 3 1","zo4 4 7"]

Note:

1. 0 <= logs.length <= 100
2. 3 <= logs[i].length <= 100
3. logs[i] is guaranteed to have an identifier, and a word after the identifier.

題目大意

Log的格式是第一個單詞是Log的索引，後面的都是Log的內容。有兩種Log，一種內容是純數字的，一種內容是純英文字元的。現在要求，把所有的英文Log放到數字Log前面。而且如果是純英文的字元Log，需要按照內容對Log進行排序，當內容相同的時候按照索引排序；如果是數字Log，保持原來的順序。

解題方法

分割和排序

周賽第一題，看起來題目很長，但是隻要是字串處理題，對於python都很簡單。首先需要進行分割成索引和內容，然後對內容的第一個單詞進行判斷，如果是英文字串，那麼把內容和索引構成tuple放到letters的列表裡；如果是數字字串，那麼直接把當前的這個log放到nums列表裡。

然後我們需要對letters進行排序，因為tuple裡首先是內容，然後是索引，所以會先對內容進行排序，然後再對索引進行排序。

把letters排序的結果重置成正常的狀態和nums拼接在一起，返回即可。

時間複雜度是O(NlogN)，空間複雜度是O(N)。

class Solution(object):
    def reorderLogFiles(self, logs):
        """
        :type logs: List[str]
        :rtype: List[str]
        """
        letters = []
        nums = []
        for log in logs:
            logsplit = log.split(" ")
            if logsplit[1].isalpha():
                letters.append((" ".join(logsplit[1:]), logsplit[0]))
            else:
                nums.append(log)
        letters.sort()
        return [letter[1] + " " + letter[0] for letter in letters] + nums

日期

2018 年 11 月 11 日 —— 剁手節快樂