// Depth First Search started from startNode
public void DFS(Node startNode)
{
// record current chain of searching
List<int> currentChain = new List<int>();
// the stack record all possible nodes to search on
Stack<Node> stack = new Stack<Node>();
// push startNode into stack
stack.Push(startNode);
while (stack.Any())
{
Node node = stack.Peek();
// if node is already in currentChain
if (currentChain.Contains(node.id))
{
// if node is the last element in currentChain
// remove node from both stack and currentChain
if (currentChain[currentChain.Count - 1] == node.id)
{
stack.Pop();
currentChain.Remove(node.id);
}
// if node is not the last elment in currentChain
// just remove node from stack
else
{
stack.Pop();
}
}
// if node is not in currentChain
else
{
// add node into currentChain
currentChain.Add(node.id);
// if node has outgoing edges
// add its outgoing nodes into stack
if (node.EdgesOut.Count > 0)
{
foreach (int i in node.EdgesOut)
{
stack.Push(nodes[i]);
}
}
// if node has no outgoing edges
// finish this path and update maxChain
else
{
updateMaxChain(currentChain);
stack.Pop();
currentChain.Remove(node.id);
}
}
}
}
// method to generate directed graph
public void generateGraph(string[] words)
{
nodes = new Node[words.Length];
for (int i = 0; i < words.Length; i++)
{
nodes[i] = new Node(i, words[i]);
for (int j = 0; j < words.Length; j++)
{
if (j == i)
continue;
if (words[j][words[j].Length - 1] == words[i][0])
nodes[i].EdgesIn.Add(j);
if (words[j][0] == words[i][words[i].Length - 1])
nodes[i].EdgesOut.Add(j);
}
}
}
