LeetCode 489. Robot Room Cleaner

[@mushiewaffle]

You have the best explanations on KZbin that I have seen! What is your background? Are you a Senior Software Engineer?

[@coolvjh]

Very well explained. Thank you 😀

[@Paunitza]

Great explanation! Thank you!

[@aunnfriends]

Here is a bit of feedback. Please zoom in the screen on the code when you are coding, otherwise it is hard to see for some other people. My eyesight is not that bad but I still need to make an effort to see the code. Keep up the good work!

[@happycoding1093]

Thanks for the feedback, I zoom to 150% in my latest video, it should be big enough.

[@mickys4999]

why do we need the below code next_d = (d + i)%4 if i use the below code like normal DFS, then why it throws recursion depth exceeded for dir in directions: new_x = x+ dir[0] next_y = y + dir[1] why robot.move() doesnt return False

[@happycoding1093]

next_d = (d + i)%4 to make sure next_d is in the range of [0,3]

[@happycoding1093]

my guess is that your robot stuck in an infinite loop, and that's why robot.move does not return False

[@nene7292]

For direction, why is up: (-1, 0) and not (0, -1)? Since the coordinate is of format (x, y), I would think the y would be -1 for up...

[@muhammadrehanalikhan1453]

its actually not (x,y) coordinate. Its rows and cols. By convention, the top left corner of 2D grid is considered (row =0, col = 0). So: incrementing row == going down & incrementing col == going right

[@yang5843]

Thank you!

[@anilkatakam2738]

Helpful. thank you.

[@vishalmishra9549]

thanks :)

[@rasi9441]

isnt it the time complexity O(N), where N is the number of cells? because each cell is visited once. I think 4^N should have been the case if we was doing repetitive work, but since we are tracking with visited, we should be okay.