/// <summary>
/// ワーシャルフロイド法
/// O(N^3)
/// </summary>
/// <param name="graph">グラフ</param>
/// <param name="nodeNum">ノードの数</param>
/// <returns>各ノード間の最短距離を辺として持つグラフ</returns>
public static WeightGraph WarshallFloyd(WeightGraph graph)
{
var res = new WeightGraph(graph);
foreach (var b in Enumerable.Range(0, graph.NodeNum))
{
foreach (var a in Enumerable.Range(0, graph.NodeNum))
{
foreach (var c in Enumerable.Range(0, graph.NodeNum))
{
res.Add(a, c, Min(res.GetLength(a, c), res.GetLength(a, b) + res.GetLength(b, c)));
}
}
}
return(res);
}
public WeightGraph(WeightGraph graph)
{
this.adjacencyMatrix = new long[graph.NodeNum, graph.NodeNum];
foreach (var i in Enumerable.Range(0, graph.NodeNum))
{
foreach (var j in Enumerable.Range(0, graph.NodeNum))
{
this.adjacencyMatrix[i, j] = graph.GetLength(i, j);
}
}
this.NodeNum = graph.NodeNum;
}