Data Engineer Interview Questions

Tiago R. - "class TrieNode { constructor() { this.children = {}; this.isEndOfWord = false; } } class Trie { constructor() { this.root = new TrieNode(); } insert(word) { let node = this.root; for (const char of word) { if (!node.children[char]) { node.children[char] = new TrieNode(); } node = node.children[char]; } node.isEndOfWord = true; } search(word) { l"See full answer

Anonymous Wasp - "I was able to provide the optimal approach and coded it up"See full answer

Tiago R. - "function permute(nums) { if (nums.length <= 1) { return [nums]; } const prevPermutations = permute(nums.slice(0, nums.length-1)); const currentNum = nums[nums.length-1]; const permutations = new Set(); for (let prev of prevPermutations) { for (let i=0; i < prev.length; i++) { permutations.add([...prev.slice(0, i), currentNum, ...prev.slice(i)]); } permutations.add([...prev, currentNum]); } return [...permutations]"See full answer

Jerry D. - "My roles included: ➢ B2B Sales of sanitary ware products to clients ➢ Sourcing of New Businesses and Managing Existing Clients ➢ Responsible for managing sales unit ➢ Developing new sales lead to meet set target. ➢ Project Management Skills: Online Sales Management · Sales Management · Customer Engagement · Sales Operations · Direct Sales · B2B Marketing"See full answer

Md kamrul H. - "public class HashMap { public class Element { T key; V value; Element(T k, V v) { this.key = k; this.value = v; } } private static final int DEFAULT_CAPACITY = 16; private static final float LOAD_FACTOR = 0.75f; private LinkedList[] table = new LinkedList[DEFAULT_CAPACITY]; private int size = 0; private int threshold = (int) (DEFAULTCAPACITY * LOADFACTOR); public void put(T k"See full answer

Rafia M. - "SQL is structured query language."See full answer

Anzhe M. - "Not my answer, but rather the details of this question. It should include the following functions: int insertNewCustomer(double revenue) -> returns a customer ID (assume auto-incremented & 0-based) int insertNewCustomer(double revenue, int referrerID) -> returns a customer ID (assume auto-incremented & 0-based) Set getLowestKCustomersByMinTotalRevenue(int k, double minTotalRevenue) -> returns customer IDs Note: The total revenue consists of the revenue that this customer bring"See full answer

Ramagiri P. - "Medallion architecture is a layered data architecture used in lakehouse systems. Data flows through Bronze, Silver, and Gold layers where each layer improves data quality. Bronze stores raw data, Silver contains cleaned and validated datasets, and Gold provides aggregated business-ready data for analytics and reporting bronzedf = spark.read.json("/landing/apidata") bronze_df.write.format("delta").save("/bronze/users")"See full answer

Reno S. - "func isMatch(text: String, pattern: String) -> Bool { // Convert strings to arrays for easier indexing let s = Array(text.characters) let p = Array(pattern.characters) guard !s.isEmpty && !p.isEmpty else { return true } // Create DP table: dpi represents if s[0...i-1] matches p[0...j-1] var dp = Array(repeating: Array(repeating: false, count: p.count + 1), count: s.count + 1) // Empty pattern matches empty string dp[0]["See full answer

Chakravarthy B. - "generally at the beginning of ever project the PgM has to come up with 5Ws & a H that translates in to a project charter. this forms the baseline expectations for a project to get kick-started."See full answer

Rajeev K. - "I’ve spent over 6 years building and scaling e-commerce products across EMEA and APAC. At Jumia, I led product initiatives on the checkout and payments side. For example, I launched gamified promotions on PDP and checkout that improved engagement and delivered a 2.3x uplift in conversion. I also introduced automated installment payments and order cancellation flows, which not only improved user trust but also reduced complaints by 30% and lowered operational costs. Before that, at Lazada, I work"See full answer

Erjan G. - "a process can include many threads. good for concurrent and parallel task execution"See full answer

Vaibhav D. - "Make current as root. 2 while current is not null, if p and q are less than current, go left. If p and q are greater than current, go right. else return current. return null"See full answer

Kunal kumar S. - "simply check its size if the size if the size is greater than n then yes it has duplicate"See full answer

Nikunj V. - "OLTP (Online Transaction Processing) and OLAP (Online Analytical Processing) are two types of data processing systems, each designed for specific purposes in the context of database and data warehouse environments. OLTP (Online Transaction Processing):Purpose: OLTP systems are designed to manage and handle high volumes of transactions, such as inserting, updating, and deleting data. These systems are typically used in day-to-day business operations. Characteristics: Handles small, si"See full answer

Tiago R. - "function isPalindrome(s, start, end) { while (s[start] === s[end] && end >= start) { start++; end--; } return end <= start; } function longestPalindromicSubstring(s) { let longestPalindrome = ''; for (let i=0; i < s.length; i++) { let j = s.length-1; while (s[i] !== s[j] && i <= j) { j--; } if (s[i] === s[j]) { if (isPalindrome(s, i, j)) { const validPalindrome = s.substring(i, j+1"See full answer