// using hash, according to req, label of nodes are unique
public UndirectedGraphNode CloneGraph(UndirectedGraphNode node)
{
if (node == null) return null;
UndirectedGraphNode res = new UndirectedGraphNode(node.label);
// store nodes
List<UndirectedGraphNode> oriNodeList = new List<UndirectedGraphNode>();
List<UndirectedGraphNode> cpyNodeList = new List<UndirectedGraphNode>();
oriNodeList.Add(node);
cpyNodeList.Add(res);
int cnt = 0;
// store the node's index
Dictionary<int, int> oriDict = new Dictionary<int, int>();
Dictionary<int, int> cpyDict = new Dictionary<int, int>();
oriDict.Add(node.label, cnt);
cpyDict.Add(res.label, cnt);
cnt++;
// pointer
UndirectedGraphNode oriNode;
UndirectedGraphNode cpyNode;
for (int i = 0; i < oriNodeList.Count;i++ )
{
oriNode = oriNodeList[i];
cpyNode = cpyNodeList[i];
foreach (UndirectedGraphNode ptrOri in oriNode.neighbors)
{
if (ptrOri == oriNode)
{
// connect to self
cpyNode.neighbors.Add(cpyNode);
}
else
{
// connect to others
int idx = -1;
if (oriDict.TryGetValue(ptrOri.label, out idx))
{
// existing ones
cpyNode.neighbors.Add(cpyNodeList[idx]);
}
else
{
// new node
UndirectedGraphNode ptrCpy = new UndirectedGraphNode(ptrOri.label);
cpyNode.neighbors.Add(ptrCpy);
oriNodeList.Add(ptrOri);
cpyNodeList.Add(ptrCpy);
oriDict.Add(ptrOri.label, cnt);
cpyDict.Add(ptrCpy.label, cnt);
cnt++;
}
}
}
}
return res;
}
// using array, exceed time limitation
public UndirectedGraphNode CloneGraph_List(UndirectedGraphNode node)
{
if (node == null) return null;
UndirectedGraphNode res = new UndirectedGraphNode(node.label);
// store nodes to visit
List<UndirectedGraphNode> oriNodeList = new List<UndirectedGraphNode>();
List<UndirectedGraphNode> cpyNodeList = new List<UndirectedGraphNode>();
oriNodeList.Add(node);
cpyNodeList.Add(res);
// pointer
UndirectedGraphNode oriNode;
UndirectedGraphNode cpyNode;
while (oriNodeList.Count > 0)
{
oriNode = oriNodeList[0];
cpyNode = cpyNodeList[0];
oriNodeList.Remove(oriNode);
cpyNodeList.Remove(cpyNode);
foreach (UndirectedGraphNode ptrOri in oriNode.neighbors)
{
if (ptrOri == oriNode)
{
// connect to self
cpyNode.neighbors.Add(cpyNode);
}
else
{
// connect to others
int idx = oriNodeList.IndexOf(ptrOri);
if (idx != -1)
{
// existing ones
cpyNode.neighbors.Add(cpyNodeList[idx]);
cpyNodeList[idx].neighbors.Add(cpyNode);
}
else
{
// new node
UndirectedGraphNode ptrCpy = new UndirectedGraphNode(ptrOri.label);
cpyNode.neighbors.Add(ptrCpy);
ptrCpy.neighbors.Add(cpyNode);
oriNodeList.Add(ptrOri);
cpyNodeList.Add(ptrCpy);
}
// remove the link to node
ptrOri.neighbors.Remove(oriNode);
}
}
}
return res;
}
static void Main(string[] args)
{
// make graph
//UndirectedGraphNode g0 = new UndirectedGraphNode(0);
//UndirectedGraphNode g1 = new UndirectedGraphNode(1);
//UndirectedGraphNode g2 = new UndirectedGraphNode(2);
//g0.neighbors.Add(g1);
//g1.neighbors.Add(g0);
//g0.neighbors.Add(g2);
//g2.neighbors.Add(g0);
//g1.neighbors.Add(g2);
//g2.neighbors.Add(g1);
//g2.neighbors.Add(g2);
// -1 1
UndirectedGraphNode g0 = new UndirectedGraphNode(-1);
UndirectedGraphNode g1 = new UndirectedGraphNode(1);
g0.neighbors.Add(g1);
//g1.neighbors.Add(g0);
Program p = new Program();
p.CloneGraph(g0);
}
