A counting Problem (codechef starters 11)

[anon74514016]

Hi everyone,
Can anyone explain me the solution of the recent contest problemA counting Problem As the official solution is not posted yet.
It would be very helpful to me if you could explain.
Thanks

[suman_18733097]

COUNTA - Editorial

PROBLEM LINK: Contest Division 1 Contest Division 2 Contest Division 3 Practice Setter: Tester: Samarth Gupta Editorialist: Taranpreet Singh DIFFICULTY Easy-Medium PREREQUISITES Dynamic Programming, Combinatorics PROBLEM Consider an array A of length N where 0 \leq A_i \leq 10^5. Construct an array B of length N-1 as B_i = min(A_i, A_{i+1}). You are given the array B, find the number of arrays A of length N, which can be used to construct array B by the above process. EXPLANATIO…