Top Data Engineer Interview Questions

Akash C. - " def longestpalindromicsubstring(s: str) -> str: if not s: return "" def expandaroundenter(left: int, right: int) -> int: while left >= 0 and right < len(s) and s[left] == s[right]: left -= 1 right += 1 return right - left - 1 start = 0 end = 0 for i in range(len(s)): len1 = expandaroundenter(i, i) len2 = expandaroundenter(i, i + 1) max_length = max(len1, len2) if"See full answer

Saurabh K. - "Missing Item - User ordered multiple items, few items are missing Wrong Item - Entire order is wrong / there are items in the order that were never ordered How is this measured ? CSAT Missing Items Wrong Items Step 1 : Collect data on orders that reported missing / wrong items. Dive deep to understand if the problem is isolated to a specific metro/zip code/restaurant type (say fast food vs fine dine), time of day (lunch vs dinner), tenure of the courier on th"See full answer

Alina G. - "SELECT upsellcampaignid, COUNT(DISTINCT trans.userid) AS eligibleusers FROM campaign JOIN "transaction" AS trans ON transactiondate BETWEEN datestart AND date_end JOIN user ON trans.userid = user.userid WHERE iseligibleforupsellcampaign = 1 GROUP BY upsellcampaignid `"See full answer

Hayatu H. - "How do you find consecutive days for login (MySQL, SQL, date, subquery, MySQL 5.7, development)? 1 Follow Request Answer More All related (34) Recommended 📷 Trausti Thor Johannsson · Follow Been using MySQL for more than 16 yearsDec 27 There are functions like DATEDIFF but there are also BETWE"See full answer

Divya R. - "static boolean sudokuSolve(char board) { return sudokuSolve(board, 0, 0); } static boolean sudokuSolve(char board, int r, int c) { if(c>=board[0].length) { r=r+1; c=0; } if(r>=board.length) return true; if(boardr=='.') { for(int num=1; num<=9; num++) { boardr=(char)('0' + num); if(isValidPosition(board, r, c)) { if(sudokuSolve(board, r, c+1)) return true; } boardr='.'; } } else { return sudokuSolve(board, r, c+1); } return false; } static boolean isValidPosition(char b"See full answer

Michelle M. - "WITH cte AS ( SELECT customer_id, COUNT(*) AS noofoffences FROM transactions WHERE receipt_number like '%999%' OR receipt_number like '%1234%' OR receipt_number like '%XYZ%' GROUP BY 1 HAVING COUNT(*) >=2 ) SELECT firstname, lastname, receipt_number, noofoffences FROM cte INNER JOIN customers using(customer_id) INNER JOIN transactions using(customer_id) ORDER BY 1,2,3,4 `"See full answer

Mohit C. - "-- LTV = Sum of all purchases made by that user -- order the results by desc on LTV select u.user_id, sum(a.purchase_value) as LTV from user_sessions u join attribution a on u.sessionid = a.sessionid group by u.user_id order by sum(a.purchase_value) desc"See full answer

Mahaboob P. - "int[] sqSorted(int[] nums) { int i = 0, j = nums.length-1; int k = nums.length-1; int[] sqs = new int[nums.length]; while(i n1) { sqs[k--] = n2; j--; } else { sqs[k--] = n1; i++; } } for(int n: sqs) System.out.println(n); return sqs; }"See full answer

Iris F. - "#include #include #include using namespace std; void printComs(int prev, int start, int end, int target) { if (start >= end) return; while (start target) { end--; } else { st"See full answer

Divya R. - "class Trie { private TrieNode root; public Trie() { root = new TrieNode(); } public void insert(String word) { TrieNode temp=root; for(int i=0; i<word.length(); i++) { if(!temp.children.containsKey(word.charAt(i))) { temp.children.put(word.charAt(i), new TrieNode()); } temp=temp.children.get(word.charAt(i)); } temp.isEndOfWord=true; } public boolean search(String word) { TrieNode temp=root; for(int i=0; i<word.length(); i++) { if(!temp.children.containsKey(word.charAt(i))) { return false; } temp"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

Anzhe M. - "It's a 2Sum question with duplicate array elements."See full answer

Ankita G. - "Merge Sort"See full answer