Q937 Reorder Log Files

Reorder Log Files

Question

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:

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

Approach 1: Custom Sort

Intuition and Algorithm

Instead of sorting in the default order, we'll sort in a custom order we specify.

The rules are:

• Letter-logs come before digit-logs;
• Letter-logs are sorted alphanumerically, by content then identifier;
• Digit-logs remain in the same order.

It is straightforward to translate these ideas into code.

class Solution(object):
    def reorderLogFiles(self, logs):
        def f(log):
            id_, rest = log.split(" ", 1) # 1的意思是按空格阶段分成2段，
                                          # 前面n-1段各自只有1个元素
            return (0, rest, id_) if rest[0].isalpha() else (1,)
                                          # 检察rest[0]是不是字符

        return sorted(logs, key = f)


def main():
    S="a1 9 2 3 1","g1 act car","zo4 4 7","ab1 off key dog","a8 act zoo"
    solution=Solution().reorderLogFiles(S)
    print(solution)


if __name__ == "__main__":
    main()

Complexity Analysis

• Time Complexity: , where is the total content of logs.

• Space Complexity: .

• Runtime: 36 ms, faster than 20.01% of Python online submissions for Reorder Log Files.

• Memory Usage: 12 MB, less than 32.91% of Python online submissions for Reorder Log Files.