/// <summary>
/// 欧拉路径(Hierholzer算法)
/// </summary>
/// <returns></returns>
public List <int> EulerLoopPath()
{
List <int> path = new List <int>();
if (!IsExistsEulerLoop())
{
return(path);
}
Stack <int> stack = new Stack <int>();
IAdjacency adjacency = _iAdjacency.Clone();
int cur = 0;
stack.Push(cur);
while (stack.Count > 0)
{
if (adjacency.Dgree(cur) != 0)
{
stack.Push(cur);
int w = adjacency.GetAllContiguousEdge(cur).First();
adjacency.RemoveEdge(cur, w);
cur = w;
}
else
{
path.Add(cur);
cur = stack.Pop();
}
}
return(path);
}
/// <summary>
/// 是否存在欧拉回路
/// </summary>
/// <returns></returns>
public bool IsExistsEulerLoop()
{
DfsGraph dfs = new DfsGraph(_iAdjacency);
if (dfs.ConnectedComponentCount > 1)
{
return(false);
}
for (int i = 0; i < _iAdjacency.V; i++)
{
if (_iAdjacency.Dgree(i) % 2 == 1)
{
return(false);
}
}
return(true);
}
