Find the shortest clear path from the top-left to bottom-right of a 0-1 grid. We explain the intuition, walk through an 8-direction BFS, add comments to every line of code, show a dry run, and give the exact time and space costs.<\/p>\n\n\n\n
Here’s the [Problem Link<\/span><\/mark><\/a><\/strong>] to begin with.<\/p>\n\n\n Given an You start at cell Return the length of the shortest<\/strong> such path (counting both start and end cells).1. What does the problem ask?<\/h2>\n\n\n\n
n \u00d7 n<\/code> binary matrix grid<\/code>:<\/p>\n\n\n\n\n
0<\/code> means an open<\/strong> cell you can walk on.<\/li>\n\n\n\n1<\/code> means a blocked<\/strong> cell you cannot step on.<\/li>\n<\/ul>\n\n\n\n(0,0)<\/code> and want to reach cell (n-1,n-1)<\/code>.
You may move to any of the 8 neighbouring cells<\/strong> (up, down, left, right, and the four diagonals) as long as<\/strong> the destination cell contains 0<\/code>.<\/p>\n\n\n\n
If no path exists, return -1<\/code>.<\/p>\n\n\n\n
\n\n\n\n2. Example<\/h2>\n\n\n\n