Practice eBay Coding Question | Real Coding Interviews

Quick Summary

Simulate a single step of a grid-based matching game.
Identify and mark bubbles meeting a neighbor-count threshold for removal.
Clear marked cells simultaneously and apply downward gravity per column.

What This Tests

Grid traversal and boundary handling
State isolation during multi-step simulations
Coordinate mapping and neighbor iteration
In-place array manipulation and element compaction

Common Patterns

Simulation

Matrix Traversal

Two Pointers

(This question is a variation of the LeetCode question 723. Candy Crush. If you haven't completed that question yet, it is recommended to solve it first.)

You are given an integer matrix bubbles, where each positive integer represents a bubble color. Two cells are orthogonal neighbors when they share a side. For example, the highlighted cells below are the orthogonal neighbors of cell A.

Test Cases

Input

Output

Expected