Student Attendance Record I — LeetCode 551 Python Solution

The problem

You are given a string s representing an attendance record for a student where each character signifies whether the student was absent, late, or present on that day. The record only contains the following three characters: 'A': Absent.

Example

Input

s = "PPALLP"

Output

true

Explanation

The student has fewer than 2 absences and was never late 3 or more consecutive days.

Python solution

class Solution:
    def checkRecord(self, s: str) -> bool:
        return s.count('A') < 2 and 'LLL' not in s

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 551. Student Attendance Record I is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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