Breadth-First Search Questions at Myntra: What to Expect

Breadth-First Search (BFS) is a fundamental algorithm for traversing graphs and trees level by level. At Myntra, a leading e-commerce platform, BFS is not just an academic concept—it's a practical tool for solving real-world problems. The platform's architecture involves product catalogs, recommendation graphs, inventory networks, and user relationship mappings, all of which are naturally modeled as graphs. Efficiently navigating these structures to find the shortest path, the nearest neighbor, or all nodes at a certain degree of separation is critical for features like "Frequently Bought Together," inventory location routing, or social features. Myntra's interview process reflects this: out of a typical set of 24 coding questions, 3 are dedicated to BFS. Mastering it demonstrates you can handle the spatial and hierarchical data problems central to their systems.

What to Expect — Types of Problems

Myntra's BFS questions typically focus on applied graph and tree traversal. You won't get a textbook "implement BFS" question. Instead, expect problems where BFS is the optimal pattern to unlock the solution.

1. Shortest Path in Unweighted Graphs: This is the most classic application. Problems may involve finding the minimum steps to reach a target in a grid (like a warehouse layout), the shortest transformation sequence, or the degrees of separation in a social network graph.
2. Level-Order Traversal & Analysis: Questions may require processing a tree level-by-level, such as calculating the average value at each level, finding the largest value on each level, or returning a zigzag level order traversal.
3. Connected Components & Flood Fill: In problems modeling contagion, region grouping, or connected inventory zones, BFS is used to explore and mark all reachable nodes from a starting point.
4. Multi-Source BFS: A common advanced twist. Instead of starting BFS from a single node, you start from multiple nodes simultaneously. This is efficient for problems like "rotten oranges" or calculating distances to the nearest service point for all nodes in a network.

How to Prepare — Study Tips with One Code Example

Focus on understanding the BFS template and recognizing when to apply it. The core pattern uses a queue to process nodes in the order they are discovered.

Key Study Tips:

• Internalize the Template: Memorize the standard BFS structure—queue, visited set, and level-by-level loop. Practice writing it from scratch.
• Map Problems to the Pattern: When you see "minimum steps," "shortest path," "level order," or "nearest distance," BFS should be your first thought.
• Practice on Grids: Many Myntra problems use a 2D grid (matrix). Be comfortable navigating up, down, left, right using direction vectors.
• Handle the Visited State: Decide what constitutes a "node" and how you will mark it as visited to prevent cycles and infinite loops.

Here is the essential BFS template for a graph, applied to a simple "shortest path length from node 0" problem:

from collections import deque

def bfs_shortest_path(graph, start):
    """
    graph: adjacency list (list of lists)
    start: starting node (int)
    Returns: list of shortest distances from start to all nodes.
    """
    n = len(graph)
    distance = [-1] * n  # -1 means unvisited
    distance[start] = 0
    queue = deque([start])

    while queue:
        node = queue.popleft()
        for neighbor in graph[node]:
            if distance[neighbor] == -1:  # Not visited
                distance[neighbor] = distance[node] + 1
                queue.append(neighbor)
    return distance

Recommended Practice Order

Build your skills progressively:

1. Fundamentals: Implement BFS on an adjacency list and a binary tree. Solve "Binary Tree Level Order Traversal."
2. Grid Traversal: Practice "Number of Islands" and "Rotting Oranges." These solidify movement in 2D space.
3. Shortest Path: Solve "Word Ladder" and "Shortest Path in Binary Matrix." These are direct applications.
4. Multi-Source BFS: Tackle "01 Matrix" (distance to nearest 0). This is a crucial pattern for Myntra's scale problems.
5. Myntra-Specific: Finally, practice problems tagged with Myntra and BFS on coding platforms to understand their exact problem style and constraints.

Practice Breadth-First Search at Myntra