Search⌘ K
AI Features
Home
Courses
Grokking the Coding Interview Patterns

Solution: Minimum Moves to Spread Stones Over Grid

Explore how to apply backtracking to solve the problem of distributing stones evenly across a 3x3 grid. This lesson guides you through identifying empty and extra stone cells, calculating moves using Manhattan distance, and using recursion and backtracking to find the minimum required moves. You will understand the process and complexity of this approach for grid-based optimization challenges.

We'll cover the following...

Statement

Given a 2D grid of integers of size (3×33 \times 3), where each value represents the number of stones in the given cell, return the minimum number of moves required to place exactly one stone in each grid cell.

Constraints:

  • Only one stone can be moved in one move.

  • Stone from a cell can only be moved to another cell if they are adjacent (share a side).

  • The sum of all stones in the grid must be equal to 99.

  • grid.length, grid[i].length ...