Coloured Pairings

You are given two sequences $A_1, A_2, \ldots, A_N$ and $C_1, C_2, \ldots, C_N$. For each valid $i$, $C_i$ is the colour of $A_i$. You should answer $Q$ queries. In each query: - You are given two colours $x$ and $y$. - Consider the subsequence of $A$ which contains only elements $A_i$ such that $C_i = x$ or $C_i = y$ (in the original order). Let's denote it by $B$. - For each contiguous sub