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

Solution: Minimum Cost to Make at Least One Valid Path in a Grid

Explore how to determine the minimum cost required to create at least one valid path from the top-left to the bottom-right cell in a directional grid. Understand the use of 0-1 BFS with a deque to efficiently process directional moves and modifications, and learn how to implement and evaluate this algorithm for optimal pathfinding under cost constraints.

We'll cover the following...

Statement

You are given an m×nm \times n grid, where each cell contains a directional sign indicating which neighboring cell to move to next. The sign in a cell grid[i][j] can be:

  • 1: Move right, i.e., from grid[i][j] to grid[i][j + 1].

  • 2: Move left, i.e., from grid[i][j] to grid[i][j - 1].

  • 3: Move down, i.e., from grid[i][j] to grid[i + 1][j].

  • 4: Move up, i.e., from grid[i][j] to grid[i - 1][j].

Note: Some signs may point outside the boundaries of the grid.

Your starting position is the top-left cell (0,0)(0, 0). A valid path is any sequence of moves beginning at (0,0)(0,0) and ending at the bottom-right cell (m−1 ...