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

Unique Paths III

Explore how to apply backtracking to solve the Unique Paths III problem, where you must find all paths from a start to an end point in a grid while visiting every empty square exactly once. Understand the grid constraints and practice coding a solution that navigates obstacles and handles four-directional movement.

We'll cover the following...

Statement

You are given a  m×nm \times n  integer array, grid, where each cell, grid[i][j], can have one of the following values:

  • 1 indicates the starting point. There is exactly one such square.

  • 2 marks the ending point. There is exactly one such square.

  • 0 represents empty squares that can be walked over.

  • -1 represents obstacles that cannot be crossed.

Your task is to return the total number of unique four-directional paths from the starting square (1) to the ending square (2), such that every empty square is visited exactly once during the walk.

Constraints:

  • ...