WA on FIBTWIST SPOJ

#1

Getting WA on spoj …all test cases passes sample and around 8-9 there also passed.

#2

Hi @piyush.bansal8158625
in dis question also, try taking fibonacci from 0.
else u can try using this formulae

calculate_fibonacci_matrix(fib, n+1);
long long fn = fib[0][1], fn_1 = fib[1][1];

    int sum = (2*(fn-1) + 2*fn_1 - n) % MOD;
    if (sum < 0) sum += MOD;

Hope dis helps.

#3

I just corrected the code and it failied too…I replied on ur previou post
I didn’t get ur sum part…ur brackets and underscores mixed up
For getting fib[1][1] i called it again having power n as it will give the same term


and last how these relations are coming… it proves but how to guess it myself

#4

@piyush.bansal8158625
its always prefered to get the basic approach to calculate transformation matrix. Deriving such formula can sometimes take a min and sometimes even a day. So, its better to follow the basic approach that prateek bhaiya must have told to form transformation matrix in these cases.like f(n)=f(n-1)+n-1,etc.

For the previous post i didnt get ur question, try messaging ur doubt in chat.
Hope dis help

#5

I have mdofied the code but still getting worng answer…used ur relation but still fails.

I didn’t knew when a non constant term is added to a recurrence. Prateek bhaiya in live class told about basic case,constant term ,and series sum if required. U can share any image for the n-1 term which is being added and how to build matrix for same. Or any link

#6

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