Round 1: Bar Raiser round Coding Question: Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's. Input: matrix = [[1,1,1],[1,0,1],[1,1,1]] Output: [[1,0,1],[0,0,0],[1,0,1]] Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]] Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]] Constraints: m == matrix.length n == matrix[0].length 1 <= m, n <= 200 -2^31 <= matrix[i][j] <= 2^31 - 1 ```java class Solution { public int[][] solve(int[][] input) { int m = input.length; int n = input[0].length; // boolean[] rows = new boolean[m]; // boolean[] cols = new boolean[n]; boolean firstRow = false; boolean firstCol = false; for(int i = 0; i < m; i++) { for(int j = 0; j < n; j++) { if (input[i][j] == 0) { if(i == 0) { firstRow = true; } if (j == 0) { firstCol = true; } input[i][0] = 0; input[0][j] = 0; } } } for(int i = 1; i < m; i++) { for(int j = 1; j < n; j++) { if (input[i][0] == 0 || input[0][j] == 0) { input[i][j] = 0; } } } if(firstRow) { for(int j = 0; j < n; j++) { input[0][j] = 0; } } if (firstCol) { for(int i = 0; i < m; i++) { input[i][0] = 0; } } return input; } } class Main { public static void main(String[] args) { // int[][] input = { // {1,1,1}, // {1,0,1}, // {1,1,1} // }; int[][] input = { {1,0,0}, {2,3,4}, {5,6,7} }; /* [ [1, 0, 0], [2, 3, 4], [5, 6, 7] ] [ [1, 2, 0], [3, 4, 0], [5, 6, 7] ] [ [1, 2, 3, 4], [5, 0, 7, 8], [0,10,11,12], [13,14,15,0] ] */ // int[][] input = { // {0,1,2,0}, // {3,4,5,2}, // {1,3,1,5} // }; Solution solution = new Solution(); input = solution.solve(input); for(int i = 0; i < input.length; i++) { for (int j = 0; j < input[i].length; j++) { System.out.print(input[i][j] + " "); } System.out.println(); } } } ``` LLD Online Marketplace - Buy & Sell Products Prompt: Design the backend components for an online marketplace where users can buy and sell products. Consider features such as user authentication, product listing, search functionality, shopping cart, and order management. 🔸 Sub-components to explore: User Authentication – Signup, Login, JWT-based session Product Listing – Sellers can create, update, delete, and view listings Search Functionality – Full-text search and filtering Shopping Cart – CRUD operations on items Order Management – Placing, viewing, and cancelling orders Distributed Architecture Questions: 1. Explain how you would ensure data consistency across multiple nodes in a distributed database. 2. Discuss the challenges and techniques for handling distributed session management. 3. Explain the role of distributed messaging systems like Kafka or RabbitMQ in a backend system.