shashiHIGS's blog

185A
By shashiHIGS, 14 years ago, In English

i think the answer is (4^n-(1+2.....(2^n-1)))%(10^9+7);but upper bound of n is 10^18; so how to find the answer?

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14 years ago, hide # |
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If I am not mistaken the answer is .
You can calculate 4n and 2n using binpow algorithm.

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