HackerEarth

Role: Problem Setter Intern

College: Tier 3 CS grad (2025)

Interview Date: May 08, 2024 (Online Assessment)

Interview Type: Internship, Off-Campus (applied via LinkedIn)

Result: Pending (Online Assessment)

Difficulty: Easy to Medium

Rounds: 1 (Online Assessment discussed)

Topics Asked: Data Structures, Algorithms, Math, String, BFS

Experience:

This candidate, a 2025 CS graduate from a Tier 3 college, applied for the HackerEarth Problem Setter Intern position via LinkedIn and immediately received an online assessment link.

Round 1: Online Assessment

The online assessment had a time limit of 1 hour 45 minutes and consisted of 3 DSA questions: 1 easy and 2 medium level problems.

• Easy Question (20 points): Given a string and an integer `k`, find the smallest character with the kth largest frequency. If no such character is found, return -1. Example: `s = "aabcd"`, `k = 2`, return 'b' (as 'b', 'c', 'd' have the 2nd largest frequency, and 'b' is the smallest). The candidate solved this using sorting and a comparator.
• Medium Question (50 points): Given integers `N`, `M`, and a matrix containing `N x M` pairs `a_ij = {x,y}` where `x` and `y` denote the jump distance from the current index `i, j`. Find the minimum number of steps required to travel from `0,0` to `N-1,M-1`. Note: If the current index is `[i,j]`, the jump can be to 8 possible cells: `[i+x,j+y]`, `[i+x,j-y]`, `[i-x,j+y]`, `[i-x,j-y]`, `[i+y,j+x]`, `[i+y,j-x]`, `[i-y,j+x]`, `[i-y,j-x]`. The candidate solved this using BFS.
• Medium Question (100 points): Given `n` and two arrays `a`, `b` of size `n`, find the number of pairs `i,j` where `0<=i,j<=n-1` such that `gcd(a[i],b[j]) != 1`. The candidate thought about solving it using an algorithm similar to the Sieve of Eratosthenes but was unable to solve it completely.