\begin{align*}
f_{\textit{score}}\{ (x_{1},\dots,x_{r})\} 
& = 
r \left (  \max_{k \in\{1,\dots,r\}} x_{k} - \min_{k \in\{1,\dots,r\}} x_{k}  \right),
\\
f_{\textit{split-score}} \{(x_{1},\dots,x_{r}),k\}
& = 
k f_{\textit{score}}\{(x_{1},\dots,x_{k})\} +  (r-k)  f_{\textit{score}}\{(x_{k+1},\dots,x_{r})\}.
\end{align*}
