hardDynamic Programming 0 views

Student Attendance Record II

An attendance record for a student can be represented as a string where each character signifies whether the student was absent, late, or present on that day.

An attendance record for a student can be represented as a string where each character signifies whether the student was absent, late, or present on that day. The record only contains the following three characters:

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

Given an integer n, return the number of possible attendance records of length n that make a student eligible for an attendance award. The answer may be very large, so return it modulo 10^9 + 7.

Example 1

Input: n = 2

Output: 8

Explanation: There are 8 records with length 2 that are eligible for an award: "PP", "AP", "PA", "LP", "PL", "AL", "LA", "LL" Only "AA" is not eligible because there are 2 absences (there need to be fewer than 2).

Example 2

Input: n = 1

Output: 3

Example 3

Input: n = 10101

Output: 183236316

Constraints

  • 1 <= n <= 10^5

Hints

No hints yet.

Companies

No companies reported yet.

Discussion

Sign in to join the discussion.

Loading discussion...

Test results

No test cases yet.