public void IndexedMinPQDecreaseKeyTest()
{
// arrange
var pq = new IndexMinPQ <string>(array);
// act + assert initial
Assert.False(pq.IsEmpty);
Assert.Equal(10, pq.Size);
Assert.Equal(3, pq.Index);
Assert.Equal(3, pq.MinIndex);
Assert.Equal("best", pq.Min);
Assert.Equal("best", pq.TopKey);
// act + assert ex
try
{
pq.decreaseKey(int.MaxValue - 1, null);
}
catch (Exception ex)
{
Assert.IsType <ArgumentOutOfRangeException>(ex);
}
try
{
pq.decreaseKey(10, null);
}
catch (Exception ex)
{
Assert.IsType <ArgumentOutOfRangeException>(ex);
}
// act + assert decrease
try
{
pq.decreaseKey(5, "zzz");
}
catch (Exception ex)
{
Assert.IsType <ArgumentException>(ex);
Assert.Equal("Calling decreaseKey() with given argument would not strictly decrease the key", ex.Message);
}
pq.decreaseKey(5, "aaa");
Assert.Equal("aaa", pq.Min);
Assert.Equal("aaa", pq.TopKey);
Assert.Equal(5, pq.Index);
Assert.Equal(5, pq.MinIndex);
}
private void scan(EdgeWeightedGraph G, int v)
{
marked[v] = true;
foreach (Edge e in G.Adj(v))
{
int w = e.other(v);
if (marked[w])
{
continue; // v-w is obsolete edge
}
if (e.Weight() < distTo[w])
{
distTo[w] = e.Weight();
edgeTo[w] = e;
if (pq.contains(w))
{
pq.decreaseKey(w, distTo[w]);
}
else
{
pq.insert(w, distTo[w]);
}
}
}
}
// relax edge e and update pq if changed
private void relax(Edge e, int v) {
int w = e.other(v);
if (distTo[w] > distTo[v] + e.weight()) {
distTo[w] = distTo[v] + e.weight();
edgeTo[w] = e;
if (pq.contains(w)) pq.decreaseKey(w, distTo[w]);
else pq.insert(w, distTo[w]);
}
}
// relax edge e and update pq if changed
private void relax(DirectedEdge e) {
int v = e.from(), w = e.to();
if (distTo[w] > distTo[v] + e.weight()) {
distTo[w] = distTo[v] + e.weight();
edgeTo[w] = e;
if (pq.contains(w)) pq.decreaseKey(w, distTo[w]);
else pq.insert(w, distTo[w]);
}
}
// scan vertex v
private void scan(EdgeWeightedGraph G, int v) {
marked[v] = true;
for (Edge e : G.adj(v)) {
int w = e.other(v);
if (marked[w]) continue; // v-w is obsolete edge
if (e.weight() < distTo[w]) {
distTo[w] = e.weight();
edgeTo[w] = e;
if (pq.contains(w)) pq.decreaseKey(w, distTo[w]);
else pq.insert(w, distTo[w]);
}
}
}
