Ooh, I see, your point makes sense. Such a silly thing I was thinking. Yeah, we will return the value according to currBoard,prevBoard,currMaxCan values because that's how recursion works.

Thanks a lot Ji_Kuai :)

We can consider bidirectional approach when-

i) Both initial and goal states are unique and completely defined. ii) The branching factor is exactly the same in both directions.

Reference — https://www.geeksforgeeks.org/bidirectional-search/

Okay, one more, Just the last one Ji_Kuai, please! Why can't we make dp[currBoard][prevBoard] storing the minimum time currently on currBoard and the last board taken be prevBoard && maxCan[currBoard][prevBoard] storing the k value when we were there. Now my claim is that dp[currBoard][prevBoard] will update only when currMaxCan is greater the maxCan[currBoard][prevBoard] or when it is not updated yet!

My code link -> 142507920

Hey, Can you please share any resource about this concept of finding gcd or about what exclusion DP is?

Thank you!

Thanks a lot!

Thank you Ji_Kuai, I was also struggling with the same thinking what's wrong in it. Thanks to nyet for replying me with the link of this comment.

But I am curious, like can't we do anything to this approach to get it better. Like at any (i,j) if we store all the possible (ans,prev) pair and using the one to calculate for further states. Tho it's more complex and inefficient. But can we do that? Will that give the right answer?

And making the conclusion that "for calculating some new dp state, the stuff we are using for it must be unique in the sense that that stuff should be only valid stuff for that previous state" is right or wrong?

Hey, I am also doing this only. But unable to figure out the mistake. Did you get to know why this will not work. Or anybody else can help us out! Please!! Thank you so much!

My Code -> 142787581 (Similar to @i_will_be_expert's)

PLEASE PLEASE, help us out!