Large Differences

You are given an array $A$ of length $N$, and a positive integer $K$. It is guaranteed that $1 \leq A_i \leq K$ for every index $i$ from $1$ to $N$. You can do the following **at most once**: - Choose an index $i$ ($1 \leq i \leq N$) and a value $x$ ($1 \leq x \leq K$). - Then, set $A_i := x$. Find the **maximum** possible value of the sum of adjacent differences of $A$ after performing this o