2018/2/10 Daily One-learning difference constraint algorithm

Differential constraint algorithm

We know that for one of the shortest-circuit problems in one side <u,v>, there must be d[v]<=d[u]+w, a slight deformation can be d[v]-d[u]<=w, is not much like x1-x2<=a this mathematical inequality?

So for an inequality group, we can convert it into a x1-x2<=a form, connect a forward edge (X2->X1), a weighted value of a, and then find the shortest way on the line.

Note If the judgment of the negative ring and the connection of the graph ...

Brush humorous and look at it.

2018/2/10 Daily One-learning difference constraint algorithm