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."
Maximize revenue from inventory sales
Problem A store has n different products. For each product i (0-indexed), you are given an integer quantity[i] representing how many units of that pro...
Implement bootstrap mean and variance
This question evaluates a candidate's ability to implement bootstrap resampling and compute statistical estimates for the sampling distribution of the...
Expected Number of Good Pairs in a Randomly Weighted Complete Graph
Expected Number of Good Pairs in a Randomly Weighted Complete Graph You are given a complete graph on n vertices — every pair of distinct vertices is ...
Smallest Palindrome Strictly Greater Than K
A palindrome is a positive integer whose decimal representation reads the same forwards and backwards, with no leading zeros. For example, 7, 44, 121,...
Count inversions in a permutation
Problem Given an array a of length n that is a permutation of distinct integers (e.g., 1..n), define an inversion as a pair of indices (i, j) such tha...
Simulate Uniform(0,1) from random bits
Assume you have access to a function rand_bit() that returns 0 or 1 with equal probability and independent across calls. How would you generate a rand...
Compute probability last passenger gets own seat
There are 100 passengers boarding a plane with 100 seats, numbered 1 to 100. Passenger i (for 1 ≤ i ≤ 100) has a ticket for seat i. The boarding proce...
Implement bootstrap mean and variance
This question evaluates the ability to implement bootstrap resampling and compute descriptive statistics, testing competency in statistical estimation...
Find kth missing integer and redundant operations
You are given two independent coding tasks. Task 1: K-th missing number You are given an integer array nums (not necessarily sorted) containing distin...
Implement monotonic-array linear interpolation
Question Implement a function interpolate(array_x, array_y, x) that returns the linearly interpolated y-value for a query x-value, given paired data p...
Implement four DS coding tasks
You are completing a CodeSignal-style assessment (Python or R). Implement solutions for the following four independent questions. 1) Two-sample z-test...
Remove shortest subarray to sort array
Given an integer array nums (length up to 2×10^5), return the shortest subarray [L,R] you can remove so that the remaining elements form a non‑decreas...
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...
Minimize L2, L1, and quantile losses
Given an array X of n real numbers, derive the value θ that minimizes the sum of squared deviations Σ(xi−θ)² (mean) and the sum of absolute deviations...
Find longest uniform substring after k replacements
Given a string s (ASCII, length up to 2e5) and integer k (0 ≤ k ≤ |s|), return the length of the longest substring that can be turned into all the sam...
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...
Implement lazy unique-merge generator for sorted streams
Write a Python generator merge_unique(a, b) that lazily merges two nondecreasing iterables a and b (potentially infinite) into a single nondecreasing ...
Compute array modes with ties and no-mode rule
Write a function that returns the mode(s) of an integer array. Requirements: if all values are unique, return an empty list (there is no mode); allow ...
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...