Problem · Matrix
Enumerate Top-to-Bottom Grid Paths
Problem statement
You are given a rectangular binary matrix grid. A cell with value 0 is open, and a cell with value 1 is blocked.
A path may start at any open cell in the top row. At each step, it may move one cell down, right, left, or up, staying inside the matrix and entering only open cells. A path is simple: it may not visit the same cell more than once. The path ends immediately when it first reaches the bottom row.
The problem statement continues
ProExamples
Example 1
grid = [[0,0],[0,0]]return = [[[0,0],[1,0]],[[0,0],[0,1],[1,1]],[[0,1],[1,1]],[[0,1],[0,0],[1,0]]]Both top-row cells are valid starts. Depth-first search uses down, right, left, then up, and stops each path as soon as it reaches row 1.
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