Student Attendance Record I

Problem Statement

In this task, you are tasked with determining whether a student qualifies for an attendance award based on a string s that records their daily attendance. This string consists of characters:

• 'A' for Absent
• 'L' for Late
• 'P' for Present

To qualify for the award, a student must satisfy the following criteria:

• They should be absent ('A') on strictly fewer than two days in total.
• They should not have three or more consecutive days marked as late ('L').

The function should return true if the student is eligible for an award, based on these conditions, and false otherwise.

Examples

Example 1

Input:

s = "PPALLP"

Output:

true

Explanation:

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

Example 2

Input:

s = "PPALLL"

Output:

false

Explanation:

The student was late 3 consecutive days in the last 3 days, so is not eligible for the award.

Constraints

• 1 <= s.length <= 1000
• s[i] is either 'A', 'L', or 'P'.

Approach and Intuition

1. Count the total number of 'A's in the string s. If there are 2 or more, we can return false since the student disqualifies based on the number of absences.

2. Check for sequences of three or more 'L's. We can iterate through the string and keep a counter for consecutive 'L's. If at any point the counter reaches 3, we return false since the student does not meet the criteria regarding consecutive lates.

3. If after scanning through the string, neither of the disqualifying conditions are met, we return true, indicating the student is eligible for the award.

By iterating through the string only once and applying the conditions as we go, this approach efficiently determines the eligibility of the student for the award. This direct approach adheres to the problem's constraints and requirements without extra computational steps.

Solutions

public class Solution {
    public boolean isEligible(String record) {
        return !record.matches(".*(A.*A|LLL).*");
    }
}