Samsung R&d

# Samsung R&D Research Intern – IIT Patna (On-Campus) Technical round. The round was mostly BFS-based problems plus OS basics. ## Round 1 – Technical Introduce yourself. **Distance to nearest 0 (01 Matrix).** Given a binary matrix, return a matrix where each cell holds the distance to the nearest 0, moving only up, down, left or right. Use a multi-source BFS that starts from all 0s together. **Word Ladder.** Given a start word, a target word and a word list, you can change one letter at a time, and every intermediate word must be in the list. Return the number of words in the shortest transformation sequence, or 0 if no such sequence exists. Treat words as graph nodes, connect two words when they differ by one letter, and run BFS from the start word. **Farthest empty cell from land.** Given an n×n grid of 1s (land/cities) and 0s (empty cells), find the empty cell whose Manhattan distance to the nearest 1 is as large as possible and return that distance (-1 if there are no 1s or no 0s). Run a multi-source BFS from every 1 at once; the last empty cell reached gives the answer. What is context switching? What is multiprocessing? Why do we need multiple processes?