Pairs Sum with Length x

Amr has given you an array $A$ of size $N$ and an integer $X$. Let $F(L, R)$ denote the number of pairs $(i,j)$ such that: - $L \le i \lt j \le R$; - $A_i + A_j$ has **exactly** $X$ digits. Your task is to calculate the value $\displaystyle{\sum_{L=1}^N \sum_{R=L+1}^N F(L, R)}$. ### Input - The first line of input will contain a single integer $T$, denoting the number of test cases. - Each test