# $k$-Link Shortest Path
- Shortest path of length $k$
- A shortest $i$-link path must be extended from a shortest $(i-1)$-link path
$
\text{path}_i(v) =
\min\begin{cases}
\text{path}_{i-1}(a) + w(a, v) \\
\text{path}_{i-1}(b) + w(b, v) \\
\dots &
\end{cases}
$
$
\text{path}_0(v) =
\begin{cases}
0, & s = v \\
\infty, & s \ne v
\end{cases}
$
- Rows for different $k$ values, columns for each vertex
- $O(kV)$ space, $O(k(V + E))$ time.
- To reconstruct the path, keep track of the pointers.