private bool HasAugmentingPath(FlowNetwork G, int s, int t)
{
_edgeTo = new FlowEdge[G.V];
_marked = new bool[G.V];
var queue = new Queue <int>();
queue.Enqueue(s);
_marked[s] = true;
while (queue.Count > 0 && !_marked[t])
{
var v = queue.Dequeue();
foreach (var e in G.Adj(v))
{
var w = e.Other(v);
if (e.ResidualCapacityTo(w) > 0)
{
if (!_marked[w])
{
_edgeTo[w] = e;
_marked[w] = true;
queue.Enqueue(w);
}
}
}
}
return(_marked[t]);
}
private double Excess(FlowNetwork G, int v)
{
var excess = 0.0;
foreach (var e in G.Adj(v))
{
if (v == e.From)
{
excess -= e.Flow;
}
else
{
excess += e.Flow;
}
}
return(excess);
}
private bool IsFeasible(FlowNetwork G, int s, int t)
{
for (var v = 0; v < G.V; v++)
{
foreach (var e in G.Adj(v))
{
if (e.Flow < Double.Epsilon || e.Flow > e.Capacity + Double.Epsilon)
{
// Sytem.err.println("Edge does not satisfy capacity constraints: " + e);
return(false);
}
}
}
if (Math.Abs(Value + Excess(G, s)) > Double.Epsilon)
{
// System.err.println("Excess at source = " + Excess(G, s));
// System.err.println("Mas flow = " + Value);
return(false);
}
if (Math.Abs(Value - Excess(G, t)) > Double.Epsilon)
{
//System.err.println("Excess at sink = " + excess(G, t));
//System.err.println("Max flow = " + value);
return(false);
}
for (int v = 0; v < G.V; v++)
{
if (v == s || v == t)
{
continue;
}
if (Math.Abs(Excess(G, v)) > Double.Epsilon)
{
//System.err.println("Net flow out of " + v + " doesn't equal zero");
return(false);
}
}
return(true);
}
