Grammarly
Online AssessmentQ1
Medium50 MarksRepeated DNA Sequences
Hash TableStringBit ManipulationSliding Window
Set 1 • 90 min
Problem Statement
In Grammarly's technical coding assessment, candidates are evaluated on clean algorithmic problem-solving for "Repeated DNA Sequences".
Given standard input parameters adhering to Hash Table principles, design an optimal algorithm that satisfies all constraints and handles boundary test scenarios efficiently.
Ensure your implementation minimizes memory overhead and executes within the allotted online assessment time limits.
Candidate Instructions
- ▸Identify the core invariant related to Hash Table.
- ▸Verify edge cases including empty inputs and extreme bounds.
- ▸Optimize time complexity before submitting.
Input Format
- ▸The first line specifies the dimensions or count of test elements N.
- ▸The subsequent line(s) contain the input array, string, or graph representation.
Output Format
- ▸Print the computed result adhering to the required return format.
Constraints
- 1 <= N <= 10^5
- -10^9 <= element[i] <= 10^9
- Time Limit: 2.0 seconds
- Memory Limit: 256 MB
Edge Cases
- ▸Empty or single-element input
- ▸Input containing maximum or minimum boundary values
- ▸Uniform elements or all-negative test cases
Sample Test Cases
Example 1
Input
nums = [1, 2, 3, 4, 5], k = 3
Output
3
Explanation
Applying the optimal Hash Table approach yields the expected solution 3.
Complexity
TimeO(N)
SpaceO(N)
Expected Approach
Leverage Hash Table combined with String, Bit Manipulation, Sliding Window, Rolling Hash, Hash Function to process the input in optimal O(N) time complexity.