Chefina and Sums

You are given a sequence $A_1, A_2, \ldots, A_N$. For each $k$ ($1 \le k \le N$), let's define a function $f(k)$ in the following way: - Consider a sequence $B_1, B_2, \ldots, B_N$, which is created by setting $A_k = 0$. Formally, $B_k = 0$ and $B_i = A_i$ for each valid $i \neq k$. - $f(k)$ is the number of ways to split the sequence $B$ into two non-empty contiguous subsequences with equal sum