Great explanation! Thank you! Could you please prepare a general video to explain how to set-up a DFS parameters and its stop condition (Many LeetCode problems similar to this but always the toughest thing is to identify what parameters are needed for the DFS)
Thanks for the detailed explanation!! I've a query, are we using cur_res as a list instead of a string because strings are immutable and addition of a character to a string takes O(N)?
Damn.. what a solution!! I was thinking of generating all expressions using recursive backtracking (by inserting operators into num at alternate places), then using the eval() function in python, evaluate the string expression and see if eval(''.join(exp)) == target, append only those exp to res. Sadly, this approach was giving a TLE 🥲 Great solution btw!
@Cracking FAANG Thanks for an AMAZING video. It's super concise and easy to understand. It's been an year but wanted to make a comment on this as I was thinking thru the complexities in the end. I am not too convinced that the Space Complexity is actually O(N), I think it should be at least O(3^N) similar to Time Complexity. I say this because I think the space needed doesn't grow linear with additional input, but rather exponentially to the additional input. Would love to know your thought on this. Thanks
because when something like this happends `1-2*3*2` you need that must be the same as `1-(x*y)` at before the `-`. If you step through the code on `1-2*3*2` it will make sense. That's what i did.
