551. Student Attendance Record I

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.
• 'L': Late.
• 'P': Present.

The student is eligible for an attendance award if they meet both of the following criteria:

• The student was absent ('A') for strictly fewer than 2 days total.
• The student was never late ('L') for 3 or more consecutive days.

Return true if the student is eligible for an attendance award, or false otherwise.

 

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.

class Solution {
    public boolean checkRecord(String s) {
        boolean hasAppeared = false;
        int lateCount = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                if (hasAppeared) {
                    return false;
                } else {
                    hasAppeared = true;
                }
            }
            
            if (s.charAt(i) == 'L') {
                if (i > 0 && s.charAt(i - 1) != 'L') {
                    lateCount = 1;
                } else {
                    lateCount++;
                }
                    
                if (lateCount >= 3) {
                    return false;
                } 
            }
        }
        return true;
    }
}