/// <summary>
/// scan vertex v
/// </summary>
/// <param name="g"></param>
/// <param name="v"></param>
private void Scan(EdgeWeightedGraph g, int v)
{
_marked[v] = true;
foreach (var e in g.Adj(v))
{
var 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continue; // v-w is obsolete edge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]);
}
}
}
}
public void IndexMinPQTest1()
{
const int MaxSize = 8;
const double MinValue = 3.9;
const double MaxValue = MinValue * MaxSize + 32;
int index;
// MinValue index == 3, MaxValue index == 4
double[] items = { MinValue * 2, MinValue * 3, MinValue * 4, MinValue, MaxValue, MinValue * 5, MinValue * 6, MinValue * 7 };
StdRandom.Seed = 101;
IndexMinPQ <double> pq = new IndexMinPQ <double>(MaxSize);
index = StdRandom.Uniform(items.Length);
Assert.IsFalse(pq.Contains(index));
Assert.IsTrue(pq.IsEmpty);
Assert.AreEqual(0, pq.Count);
try
{
index = pq.DelMin();
Assert.Fail("Failed to catch exception");
}
catch (InvalidOperationException) { }
for (int i = 0; i < items.Length; i++)
{
pq.Insert(i, items[i]);
}
Assert.AreEqual(items.Length, pq.Count);
Assert.AreEqual(MinValue, pq.MinKey);
Assert.AreEqual(3, pq.MinIndex);
Assert.AreEqual(MaxValue, pq.KeyOf(4));
index = StdRandom.Uniform(items.Length);
Assert.AreEqual(items[index], pq.KeyOf(index));
pq.ChangeKey(1, pq.MinKey * 0.9); // make it the smallest item
Assert.AreEqual(1, pq.MinIndex);
pq.DecreaseKey(3, pq.MinKey * 0.87);
Assert.AreEqual(3, pq.MinIndex);
pq.Delete(3);
Assert.AreNotEqual(3, pq.MinIndex);
Assert.AreEqual(1, pq.DelMin());
}
/// <summary>
/// relax edge e and update pq if changed
/// </summary>
/// <param name="e"></param>
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]);
}
}
}
/// <summary>
/// relax edge e and update pq if changed
/// </summary>
/// <param name="e"></param>
/// <param name="v"></param>
private void Relax(EdgeW e, int v)
{
var 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]);
}
}
}
private void Visit(WeightedGraph G, int v)
{
marked[v] = true;
foreach (var e in G.adj(v))
{
int w = e.other(v);
if (!marked[w])
{
if (!pq.Contains(w))
{
pq.Insert(w, e);
}
else
{
pq.DecreaseKey(w, e);
}
}
}
}
/// <summary>
/// relax edge e and update pq if changed
/// relax defined as follows: to relax an edge v-->w means to test whether the best known way from s to w is to go from s to v, then take the edge from v to w.If so, update our data structures to indicate that
/// </summary>
/// <param name="e"></param>
private void relax(DirectedEdge e)
{
int v = e.From();
int 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]);
}
}
}
private void Relax(WeightedDiGraph G, Edge e)
{
int v = e.from();
int w = e.to();
if (cost[w] > cost[v] + e.Weight)
{
cost[w] = cost[v] + e.Weight;
edgeTo[w] = e;
if (!pq.Contains(w))
{
pq.Insert(w, cost[w]);
}
else
{
pq.DecreaseKey(w, cost[w]);
}
}
}
protected void Relax(IndexMinPQ <double> pq, DirectedEdge e)
{
int v = e.From;
int 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
{
//this will never used
pq.Insert(w, distTo[w]);
}
}
}
// Returns shortest path from src to dst (not including src)
public List <TileNode> GetShortestPath(Vector2Int src, Vector2Int dst, UnitType unitType)
{
float[,] distance = new float[width, height];
Vector2Int[,] prev = new Vector2Int[width, height];
IndexMinPQ <float> minPQ = new IndexMinPQ <float>(width * height);
distance[src.x, src.y] = 0.0f;
prev[src.x, src.y] = src;
minPQ.Insert(ToTileIndex1D(src), 0.0f);
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
if (i == src.x && j == src.y)
{
continue;
}
distance[i, j] = float.PositiveInfinity;
prev[i, j] = new Vector2Int(-1, -1);
minPQ.Insert(ToTileIndex1D(i, j), float.PositiveInfinity);
}
}
while (!minPQ.IsEmpty)
{
float dist = minPQ.MinKey;
Vector2Int min = ToTileIndex2D(minPQ.DelMin());
Vector2Int[] neighbors = GetNeighbors(min);
foreach (Vector2Int neighbor in neighbors)
{
int neighborInd = ToTileIndex1D(neighbor);
float edgeDist = GetTileMoveWeight(neighbor, unitType);
if (minPQ.Contains(neighborInd) && edgeDist != 0.0f)
{
float currentDist = minPQ.KeyOf(neighborInd);
if (dist + edgeDist < currentDist)
{
distance[neighbor.x, neighbor.y] = dist + edgeDist;
prev[neighbor.x, neighbor.y] = min;
minPQ.DecreaseKey(neighborInd, dist + edgeDist);
}
}
}
}
if (distance[dst.x, dst.y] == float.PositiveInfinity)
{
return(null);
}
List <TileNode> path = new List <TileNode>();
TileNode dstNode;
dstNode.coords = dst;
dstNode.dist = distance[dst.x, dst.y];
path.Add(dstNode);
Vector2Int tile = dst;
while (prev[tile.x, tile.y] != src)
{
tile = prev[tile.x, tile.y];
TileNode node;
node.coords = tile;
node.dist = distance[tile.x, tile.y];
path.Add(node);
}
path.Reverse();
return(path);
}
