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

Solution: Unique Paths III

Explore the backtracking technique to solve the Unique Paths III problem by recursively finding all valid paths from the start to the end point in a grid. Understand how to handle obstacles and ensure each empty cell is visited exactly once. Learn to implement this efficient recursive strategy and evaluate its time and space complexities.

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 ...