Data Scientist Coding & Algorithms Interview Questions
Practice 335 real Coding & Algorithms interview questions for Data Scientist roles. From companies including Amazon, Google, Two Sigma, Pinterest, Uber.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Compute max island with constrained flips
Given an n×n binary grid G where 1=land and 0=water with 4-directional connectivity, return the size of the largest island achievable by flipping at m...
Implement anagram check and stable deduplication
Part A — Anagram checker: Write a function is_anagram(a: str, b: str, locale: str = 'en') -> bool that returns True iff a and b are anagrams under the...
Solve stock, BFS path, and merge intervals
Solve three coding problems; justify complexity and corner cases. A) Best Time to Buy/Sell Stock (one transaction): Given prices[0..n-1] (integers), r...
Solve and optimize 3Sum and variants at scale
Implement a function that returns all unique triplets (i, j, k) of indices whose values sum to a target T, with strong performance and deduplication g...
Implement DFS with cycle detection and topo order
Implement DFS (recursive and iterative) with topo sort, cycle detection, and timestamps You are given a directed graph G with N nodes labeled 1..N and...
Implement streaming per-user reservoir sampling
Design and code (in Python) a streaming algorithm that ingests an unbounded event stream of tuples (user_id, event_time, event_type) and maintains, fo...
Solve two-pointer, sliding-window, and string tasks
Solve the following three coding tasks: 1) Two-pointer in-place de-duplication: Given a non-decreasing integer array nums and an integer k >= 1, modif...
Check anagrams under real-world constraints
Given two strings s and t, determine whether they contain exactly the same multiset of characters (e.g., 'abc' and 'cab' → true; 'aab' and 'ab' → fals...
Implement scalable prime generator
Write a function first_n_primes(n) that returns the first n prime numbers in ascending order. Constraints: - 1 ≤ n ≤ 100,000. - Aim for O(n log log n)...
Implement streaming CTR with deduplication
Implement a Python function to compute streaming, per-campaign CTR over a sliding 24-hour window with click de-duplication and late-arriving events. R...
Implement rotated array binary search with duplicates
Given an integer array nums that is a non-decreasing array rotated an unknown number of times. Duplicates may exist. Implement a function that returns...
Reverse a singly linked list robustly
Reverse a Singly Linked List In-Place Context: You are given the head of a standard singly linked list (each node has value and next). Implement and e...
Check if a numeric string is divisible by 8
Question You are given a very large non-negative integer represented as a decimal string s (it may be too large to fit in standard 64-bit integer type...
Compute square root to 1 decimal
Problem Given a non-negative real number x, implement a function sqrt1dp(x) that returns \(\sqrt{x}\) rounded (or truncated—clarify with interviewer) ...
Implement drawdown, single-trade profit, coin change
Implement and analyze the following three problems: 1) Maximum drawdown of cumulative PnL: "What is the maximum drawdown of a cumulative PnL (profit a...
Compute maximum beauty of a string
Given a string s, define the beauty of each letter a–z as a distinct integer between 1 and 26, case-insensitive. The beauty of a string is the sum ove...
Implement an LRU Cache
Problem: LRU Cache (LeetCode 146) Design and implement a Least Recently Used (LRU) Cache that supports the following operations in average O(1) time. ...
Compute rolling standard deviation in O(n)
Compute rolling standard deviation in O(n) Given an array of numbers and a window size k, compute the rolling standard deviation for every contiguous ...
Compute drawdown, profit, and coin change
Question What is the maximum drawdown of a cumulative PnL (profit and loss) series, and when did it occur? Implement a function mdd(pnl) that returns ...
Implement Cosine Similarity Function for String Vectors
Scenario Technical phone screen in Python; assess ability to implement similarity metric. Question Implement a Python function that computes the cosin...