What is the fastest known algorithm for max flow on dags?
Can there be a linear-time algorithm running in time $O(|V|+|E|)$?
Input: a weighted dag $G=(V,E,w)$ where
$E$ is given as an edge list $E$ and
$w$ is the edge weight function; and
two vertices $s$ and $t$.
Output: a max flow from $s$ to $t$.
The dag is simple (no loops, no parallel edges).
Edge weights are positive integers.