Spp recursive sequence

#1

I am getting error time limited exceeded.
code link:

#2

Hey your code has very high time complexity O(t(n-m)). And n - m could be upto 10^18 which makes this solution infeasible.

        for(int i=n ;i<=m ;i++){
          ans = ((ans%MOD)+ (compute(i)%MOD))%MOD;
        }

What you should have done is find sum of first n elements and find sum of first m - 1 elements. And subtract them to get sum of element in range(m, n). You need to find the sums using matrix exponentiation (O(logn)) time.

#3

can you share your code

#4

Or you can also see this.

#5

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