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How to Solve Student Attendance Record II Problem
Master the Student Attendance Record II LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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LeetCode ProblemStudent 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. 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 109 + 7.
Dynamic Programming
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Problem Breakdown
Understanding the Student Attendance Record II Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
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 109 + 7.
HardProblem #552
LeetCodeStudent Attendance Record II
Related Topics
Dynamic Programming
How Phantom Code AI Helps
Get real-time assistance for Student Attendance Record II problems during coding interviews. Phantom Code AI provides instant solutions and explanations.
Examples
# Example 1
Input
n = 2
Output
8
# Example 2
Input
n = 1
Output
3
# Example 3
Input
n = 10101
Output
183236316
Constraints
1 <= n <= 105
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Solve Student Attendance Record II — An attendance record for a student can be represented as a string where each cha...
Here's the optimal approach using Dynamic Programming:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Student Attendance Record II and using Phantom Code AI during coding interviews.
How does Phantom Code AI help me solve coding problems like Student Attendance Record II during interviews?
Phantom Code AI generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Student Attendance Record II?
Phantom Code AI adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
Can Phantom Code AI help me communicate my solution for problems like Student Attendance Record II?
Yes. Phantom Code AI provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code AI assist with different programming languages for Student Attendance Record II type problems?
Phantom Code AI supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code AI help me avoid during Student Attendance Record II interviews?
Phantom Code AI catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code AI detectable when solving problems like Student Attendance Record II during live interviews?
No. Phantom Code AI runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code AI help when I'm struggling with Student Attendance Record II style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code AI work for the coding platforms used in Student Attendance Record II interviews?
Yes. Phantom Code AI works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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