FIBEASY September Long 2019

general
27

https://www.codechef.com/viewsolution/26625992

Here is the fixed answer

I just did this

        ll index=pow(2,y);
        //cout<<index<<endl;
        cout<<findLastDigit(index%60 -1)<<endl;
28

I know it’s dumb to ask because I’m beginner in ds and algo. Where you learnt that 10^8 is max memory allocation for the array?

29

Honestly… i think i read somewhere on internet…i don’t remember where :laughing:

30

Maximum size of the array: We must be knowing that the maximum size of array declared inside the main function is of the order of 10^6 but if you declare array globally then you can declare its size upto 10^7

17-00_08_52
17-00_08_52926×131 15.5 KB

Ref: Geeksforgeeks

31

According to Geeks for Geeks, it should be 10^7. Isn’t right??

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17-00_08_52926×131 15.5 KB

32

Use exp2l() function, Its better than pow() function.

    cin >> n;
    n = log2l(n);
    n = exp2l(n) - 1;
    cout << f[n % 60] << "\n";
33

You can use up to 10^8. I also read it somewhere :sweat_smile::sweat_smile: But that you have to declare globally. And I also tried it creating the global array with size 10^8. And up to 10^6 is advised inside the function.

34

Although the size of array also depends upon whether you want to create integer array or character array. Along with that it also depends on your hardware.

35

Using log2() will give WA for the following testcase:

1
18014398509481983

Output should be 9.

36

have you even tried on his solution?
works fine riNeF6 - Online C++0x Compiler & Debugging Tool - Ideone.com

37

Got it. I was doing index-1 % 60. Cheers.

1 Like
38

Was meant as an announcement for the people who were wondering why log2() was not working, I’m the problem setter. Replied on your comment by mistake, this wasn’t supposed to be a reply.

39

That’s awesome ! :smile:

40

How did you come up with this logic bro:)

41

@warg Can you please explain your logic??
How did you came up with this??

42

by observing the pattern while doing { \mod}10

1 Like
43

Yes by observing the pattern. I checked manually for the small nos. And verified the logic using python (it allows you to work with very very large nos. Easily) and after that I gave it a try.

1 Like
44

This will help you alot : Easy Fibonacci | September long challenge 2019 | Codechef Solutions & Code || FIBEASY | Hello World - YouTube

1 Like
45

This will help you alot : Easy Fibonacci | September long challenge 2019 | Codechef Solutions & Code || FIBEASY | Hello World - YouTube
thanks

46

Thanks @warg and @syntaxhacker. :smiley: