[Leetcode]937 : Reorder Data in Log Files

Link : https://leetcode.com/problems/reorder-data-in-log-files/

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

There are two types of logs:

• Letter-logs: All words (except the identifier) consist of lowercase English letters.
• Digit-logs: All words (except the identifier) consist of digits.

Reorder these logs so that:

1. The letter-logs come before all digit-logs.
2. The letter-logs are sorted lexicographically by their contents. If their contents are the same, then sort them lexicographically by their identifiers.
3. The digit-logs maintain their relative ordering.

Return the final order of the logs.

圖來自leetcode

Thoughts :
0. 分兩個 array 存。一個存 letter、一個存數字
1. 確認當前的 log 是 letter 還是數字。
2. 如果是 letter 存到 letter 陣列，如果是非 letter 存到nums陣列。
3. letter 的 array 做 sort、nums的按照原本的排序就好。

Solution :

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

time complexity = O(nlog n), space complexity = O(n)