The document discusses the maximal flow problem and its technique. The maximal flow problem aims to compute the maximum possible flow that can leave the source and enter the sink. The maximal flow technique involves 5 steps: 1) choosing a path from source to sink, 2) finding the path with the lowest flow capacity, 3) subtracting the lowest capacity in the source to sink direction and adding it in the reverse direction, 4) completing the addition and subtraction for the first iteration, and 5) repeating steps 1-4 until all paths have a zero flow capacity from source to sink.