Happy number | Leetcode 

thanks

I have posted in community. Follow my video on kadane's algorithm. You will understand it. That's why I did not post Day-3 video. Today I will post Day-4 video.

@@techdose4u okk sir

That is trial n error. It can vary with test cases. Best method is to use SET. But that was just to improve time complexity. It was just a hunch. If your number is happy then it should not require a lot of operations. Try to solve some using pen n paper. You can also create a code using a random generator as input and take a variable to count how if a number is happy then just return the no of steps done. In that way you can store the Max value and figure out how many steps you need. It will be a simple code. Use SET to verify the Max step count.

You need to take a number which will be an upper bound for all the test cases. I have not explained you the proof but if you think a little then you will get it.

Yea correct. Actually set is also O(1) space because your cycle will be short.

@@techdose4u how do we know cycle will be short ??

Floyd hare and tortoise algorithm right ???

@@crimsoncad3230 yes.

Just a hunch. I have no mathematical proof. See my 2nd method code. You might get it.

You can find out the Max steps needed but writting a function and passing all possible inputs.

@@techdose4u OK thanks sir U r voice is great sir Yours presentation ,usage of words both are good sir

You can find the value of counter. I did it by trial and error but you can see the range and test it to find proper value of counter.

Yea... :)

Since all test cases were available, I did trial and error. If they are not available. Then you can just return the length instead of true or false. In that way, you can keep track of length of largest reduction chain encountered. Take +1 length for your loop and that's it. This is not trial and error. I hope you got it.

Thanks :)

True. Some platforms do not allow java and python any extra time. So, for competitive programming, C++ is preferable.

@@techdose4u I was fortunate in the 1st Problem i.e Single Number I wrote the solution in Python and it did accept it.

@@techdose4u When I see HackerRank and HackerEarth have adapted to the changes but LeetCode being the top coding platform in the world is yet to adapt/make changes, this thing amazes me.

@@crimsoncad3230 It means you have to optimized your code. I submitted my code in python.

Share your DS and technique bro. He will also get it.

Thanks :)

👍

Thanks :)

You need to use loop because you don't know the length of any number.

@@techdose4u okk sir.

Yes you can by converting it to a string.

Which problem? I have recently made painters partition problem. Check it out.

@@techdose4u www.geeksforgeeks.org/partition-problem-dp-18/amp/

Sir the above problem problem along with the partitoned parts.

Sure :)

It can be improved using hash table instead of red black tree (unordered_map instead of set) Because lookup is O(1) vs O(log N)

Welcome 😊

Welcome