551. Student Attendance Record I

Question

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.

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'.

References

来源：力扣（LeetCode） 链接：https://leetcode-cn.com/problems/student-attendance-record-i 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

Solutions

暴力

class Solution {
    public boolean checkRecord(String s) {
       int absent = 0;
        int late = 0;

        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                absent++;
            }
            if (i > 0 && s.charAt(i - 1) != 'L') {
                late = 0;
            }
            if (s.charAt(i) == 'L') {
                late++;
            }
            if (absent >= 2 || late >= 3) {
                return false;
            }
        }
        return true;
    }
}

一行代码

class Solution {
    public boolean checkRecord(String s) {
        return !s.contains("LLL") && s.indexOf("A") == s.lastIndexOf("A");
    }
}