Cracking Meta's Software Engineer Interview: Tackling Tough Coding Challenges

Software Engineering
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meta | Software Engineer | Interview Experience

Interview Date: Not specified
Result: Not specified
Difficulty: Not specified

Interview Process

The interview consisted of multiple coding questions focused on algorithm and data structure challenges. The format included live coding on a shared document, with the interviewer asking clarifying questions and discussing the approach during the coding process.

Technical Questions

  1. Cost Minimization Problem
    You are given two integer arrays of equal length D and R. D is the cost of departing on day i, and R is the cost of returning on day i. You need to plan a round trip by choosing one departure day and one return day such that:

    • The return day is strictly after the departure day.
    • The total cost is minimized.
      Return the minimum possible total cost. If no valid trip exists, return -1.
      Example:
    D = [2, 5, 3, 4, 5]  
R = [5, 3, 5, 1, 6]  
Output: 3  
Explanation: Depart on day 0 (cost 2), return on day 3 (cost 1).

  2. Pathfinding in a Grid
    You are given a 2D grid where 0 represents an open cell and 1 represents a blocked cell. Starting at the top-left corner (0, 0), your goal is to reach the bottom-right corner (m-1, n-1). You can move up, down, left, or right, but cannot pass through cells with 1.
    Return any one valid path as a list of coordinates. If no path exists, return an empty list.
    Example:

    grid = [[0, 0, 0], 
        [0, 1, 0], 
        [0, 0, 0]]  
Output: [(0,0), (0,1), (0,2), (1,2), (2,2)]

  3. Largest New Island Problem
    You are given a 2D grid consisting of 0s and 1s, where 1 represents an existing island cell and 0 represents water. You want to create a new island by converting some 0s into 1s, with the restriction that your new island must NOT be 4-directionally adjacent to any existing island cells.
    Return the size of the largest possible new island you can create. If no valid new island can be formed, return 0.
    Example:

    grid = [[1,0,0,0], 
        [0,0,0,1], 
        [0,0,0,0]]  
Output: 2  
Explanation: The largest new island you can form is of size 2.

  4. Change Directory Command Implementation
    Implement a function that mimics the behavior of the Linux cd (change directory) command. You are given two paths: dir1 (the current working directory) and dir2 (the target path).

    • If dir2 starts with ‘/’, treat it as absolute and ignore dir1.
    • If dir2 is relative, apply it starting from dir1.
    • Return the final absolute path.
      Example:
    dir1 = "/usr/bin"  
dir2 = "../lib"  
Output: "/usr/lib"

Tips & Insights

  • Focus on understanding the problem requirements thoroughly before starting to code.
  • Break down the problem into smaller parts and tackle them one at a time.
  • Practice coding problems that involve arrays and grid traversal to prepare for similar questions in interviews.