Data Scientist Coding & Algorithms Interview Questions
Practice 316 real Coding & Algorithms interview questions for Data Scientist roles. From companies including Amazon, Google, Pinterest, Uber, Capital One.
"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."
Find minimum swaps to sort array with duplicates
Problem Given an integer array nums of length n that may contain duplicate values, you may perform swaps where you choose any two indices i and j and ...
Calculate Jaccard Similarity Score for Two String Lists
Scenario During pair programming, the interviewer asks you to compare two lists of merchant tags and quantify their similarity. Question Implement a P...
Merge Two Sorted Lists
You are given the heads of two singly linked lists, each already sorted in non-decreasing order. Merge them into one sorted linked list and return the...
Move zeros to front
Given an integer array nums, move all 0 values to the beginning of the array in place while preserving the relative order of all non-zero elements. Re...
Explain list vs tuple in Python
Question In Python: 1. What are the key differences between a list and a tuple? 2. When would you prefer using a tuple over a list? 3. What are the pe...
Design late-tolerant streaming window aggregator
You receive an unbounded stream of events: (event_time, user_id, category). Events may arrive up to 48 hours late and are not ordered by time. Design ...
Maximize products bought under budget
Given N products and M customers, for each customer find the list of distinct products they can buy without exceeding their budget such that the numbe...
Debug and test a Python function in venv
Consider the Python snippet below. """ import math def accumulate(nums, start=0, cache={}): total = start for n in nums: if n % 2 == 0: nums.appen...
Infer and justify non-trivial sequence patterns
Pattern Recognition: Next Terms and Missing Value Identify the rule governing each sequence or row and compute the missing value(s). Justify each answ...
Solve two string DP/hash problems
Solve the following two coding questions. 1) Unique Morse Code Transformations You are given an array of strings words (lowercase English letters). Us...
Implement Plus One
Given a non-empty array of digits representing a non-negative integer, where the most significant digit comes first and each element is in [0, 9], add...
Convert a PDF to a CDF
Given a continuous random variable X with probability density function f(x), write code or describe an algorithm to construct its cumulative distribut...
Compute statistics in data stream
Question Design a data structure that supports computing the current max, mean, and mode for an unbounded integer data stream. Estimate the memory usa...
Compute Minimum Parentheses Additions
Given a string s consisting only of the characters '(' and ')', compute the minimum number of parentheses that must be inserted anywhere in the string...
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 window. Design an O(n) algorithm that updat...
Optimize invites under capacity constraints
You have n donors (n up to 100,000). For each donor i you know: p_online[i] (probability of donating if emailed), a_online[i] (expected donation condi...
Compute precision–recall curve on imbalanced data
You receive a CSV with columns: actual_label ∈ {0,1} and predicted_prob ∈ [0,1]; the positive class rate is ≈5%. a) Which evaluation metrics would you...
Implement an LRU cache with O(1) ops
Design and code an LRU cache supporting get(key) and put(key, value) in O(1) average time with capacity N. Specify your data structures, handle update...
Detect k events in a sliding window
Implement an algorithm that, for each user, determines whether there exists a set of at least k ACH credit events from distinct device_ids within any ...
Optimize assembly-line scheduling with changeovers
You are scheduling a simplified car-assembly line with two parallel stations S1 and S2. Each job must be processed on exactly one station, processing ...