551. Student Attendance Record I

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.

• '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.

  Constraints:

• 1 <= s.length <= 1000

• s[i] is either 'A', 'L', or 'P'.

Solution (Java)

class Solution {
    public boolean checkRecord(String s) {
        int aCount = 0;
        int i = 0;
        while (i < s.length()) {
            if (s.charAt(i) == 'A') {
                aCount++;
                if (aCount > 1) {
                    return false;
                }
            } else if (s.charAt(i) == 'L') {
                int continuousLCount = 0;
                while (i < s.length() && s.charAt(i) == 'L') {
                    i++;
                    continuousLCount++;
                    if (continuousLCount > 2) {
                        return false;
                    }
                }
                i--;
            }
            i++;
        }
        return true;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).