Skip to content

551. Student Attendance Record I 👍

  • Time: $O(n)$
  • Space: $O(1)$
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
class Solution {
 public:
  bool checkRecord(string s) {
    int countA = 0;
    int countL = 0;

    for (const char c : s) {
      if (c == 'A' && ++countA > 1)
        return false;
      if (c != 'L')
        countL = 0;
      else if (++countL > 2)
        return false;
    }

    return true;
  }
};

1
2
3
4
5
class Solution {
  public boolean checkRecord(String s) {
    return s.indexOf("A") == s.lastIndexOf("A") && !s.contains("LLL");
  }
}

1
2
3
class Solution:
  def checkRecord(self, s: str) -> bool:
    return s.count('A') <= 1 and 'LLL' not in s