private static void BuildPath(TreeNode currentNode, Stack<TreeNode> shortestSequence)
{
if (currentNode.Parent != null)
{
shortestSequence.Push(currentNode.Parent);
BuildPath(currentNode.Parent, shortestSequence);
}
}
private static void FillTree(TreeNode treeNode, int endValue)
{
int currentValue = treeNode.Value;
int childValue;
TreeNode childNode;
if (currentValue < endValue)
{
foreach (var operation in operations)
{
childValue = operation(currentValue);
childNode = new TreeNode(childValue, treeNode);
treeNode.Children.Add(childNode);
FillTree(childNode, endValue);
}
}
else
{
return;
}
}
static void Main(string[] args)
{
int n = 5;
int m = 16;
int level = 0;
bool isFoundLevel = false;
Stack<TreeNode> shortestSequence = new Stack<TreeNode>();
TreeNode root = new TreeNode(n, null);
List<TreeNode> foundNodes = new List<TreeNode>();
FillTree(root, m);
if (n < m)//http://en.wikipedia.org/wiki/Breadth-first_search
{
TreeNode currentNode;
Queue<TreeNode> treeNodes = new Queue<TreeNode>();
treeNodes.Enqueue(root);
while (treeNodes.Count > 0)
{
currentNode = treeNodes.Dequeue();
if (currentNode.Value == m)
{
if (!isFoundLevel || (isFoundLevel && currentNode.Level == level))
{
foundNodes.Add(currentNode);
level = currentNode.Level;
isFoundLevel = true;
}
}
else if (currentNode.Value < m && isFoundLevel == false)
{
foreach (TreeNode node in currentNode.Children)
{
treeNodes.Enqueue(node);
}
}
}
string shortestPath = string.Empty;
if (foundNodes.Count != 0)
{
StringBuilder sb = new StringBuilder();
foreach (TreeNode nodeItem in foundNodes)
{
shortestSequence.Clear();
shortestSequence.Push(nodeItem);
BuildPath(nodeItem, shortestSequence);
foreach (TreeNode node in shortestSequence)
{
sb.AppendFormat("{0} ", node.Value);
}
sb.AppendLine();
}
shortestPath = sb.ToString();
}
else
{
shortestPath = "Path not found!";
}
Console.WriteLine(shortestPath);
}
}
public TreeNode(int value, TreeNode parent)
{
this.value = value;
this.parent = parent;
this.children = new List<TreeNode>();
if (parent == null)
{
this.level = 0;
}
else
{
this.level = this.Parent.Level + 1;
}
}
