I am solving a coding question and term is:
(t+1)!+(t+2)!/2!+......(t+n)!/n!
1<=t<=1000
1<=n<=10^11
and answer should be in modulo 1000000007 (10^9+7).
So I wrote code in cpp to find (t+1)!. So I am having (t+1)!. Now what are the approaches to solve it?
- I don't want to find factorial of each term because is expensive. I want to use the
(t+1)!term for rest of the terms. - I want to find modulo of each individual term and then find modulo of whole term using modulo property.