public static void Main(string[] args)
{
int nodeCount = int.Parse(Console.ReadLine());
var tree = new Tree();
for (int i = 1; i < nodeCount; i++)
{
var edge = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
var parentValue = edge[0];
var parentNode = tree.GetTreeNodeByValue(parentValue);
var chieldValue = edge[1];
var chieldNode = tree.GetTreeNodeByValue(chieldValue);
chieldNode.Parent = parentNode;
parentNode.Children.Add(chieldNode);
}
var pathSum = int.Parse(Console.ReadLine());
var subreeSum = int.Parse(Console.ReadLine());
var rootNode = tree.FindRootNode();
Console.WriteLine("First Node: {0}", rootNode.Value);
var leafs = tree.FindAllLeafs().Select(l => l.Value);
Console.WriteLine("Leaf nodes: {0}", string.Join(", ", leafs));
var middleNodes = tree.FindAllMiddleNodes().Select(l => l.Value);
Console.WriteLine("Middle nodes: {0}", string.Join(", ", middleNodes));
var longesPath = tree.FindLongestPath().Select(l => l.Value);
Console.WriteLine("Longest path: {0} (length = {1})",
string.Join(" -> ", longesPath), longesPath.Count());
var sumPaths = tree.FindAllPathsWithGivenSum(pathSum);
Console.WriteLine("Path of sum: {0}", pathSum);
foreach (var sumPath in sumPaths)
{
var path = sumPath.Select(p => p.Value);
Console.WriteLine("{0}", string.Join(" -> ", path));
}
}
static void Main()
{
int nodesCount = int.Parse(Console.ReadLine());
var tree = new Tree();
for (int i = 1; i < nodesCount; i++)
{
string[] edge = Console.ReadLine().Split(' ');
int parentValue = int.Parse(edge[0]);
Tree parentNode = tree.GetTreeNodeByVlue(parentValue);
int childValue = int.Parse(edge[1]);
Tree childNode = tree.GetTreeNodeByVlue(childValue);
parentNode.Children.Add(childNode);
childNode.Parent = parentNode;
}
int pathSum = int.Parse(Console.ReadLine());
int subtreeSum = int.Parse(Console.ReadLine());
var middleNodes = tree.FindMiddleNodes().Select(m => m.Value);
var leafs = tree.FindAllLeafs().Select(l => l.Value);
var longestPath = tree.FindLongestPath().Select(l => l.Value);
var sumOfElemetns = tree.PathsOfSum(pathSum);
foreach (var sumOfElement in sumOfElemetns)
{
var path = sumOfElement.Select(s => s.Value);
Console.WriteLine(string.Join(", ", path));
}
}
static Tree<int> GetNodeByValue(int value)
{
if (!nodeByValue.ContainsKey(value))
{
nodeByValue[value] = new Tree<int>(value);
}
return nodeByValue[value];
}
private List<Tree> FindLongestPath(Tree node, List<Tree> elements, List<Tree> bestElements)
{
var children = node.Children;
foreach (var child in children)
{
elements.Add(child);
if (child.Children.Count != 0)
{
bestElements = this.FindLongestPath(child, elements, bestElements);
}
if (elements.Count > bestElements.Count)
{
bestElements = elements;
}
elements = new List<Tree>();
}
return bestElements;
}
private static List<Tree> GetElementsSoFar(Tree child)
{
var elements = new List<Tree>();
var parent = child.Parent;
while (parent != null)
{
elements.Insert(0, parent);
parent = parent.Parent;
}
return elements;
}
private List<List<Tree>> PathsOfSum(Tree firstNode, List<Tree> currentElements, List<List<Tree>> sumOfElements, int result)
{
var children = firstNode.Children;
foreach (var child in children)
{
currentElements.Add(child);
if (currentElements.Sum(e => e.Value) == result)
{
sumOfElements.Add(currentElements);
currentElements = GetElementsSoFar(child);
}
if (child.Children.Count != 0)
{
sumOfElements = this.PathsOfSum(child, currentElements, sumOfElements, result);
}
currentElements = GetElementsSoFar(child);
}
return sumOfElements;
}
static int TreeSum(Tree<int> tree)
{
return tree.Value + tree.Children.Select(s => s.Value).Aggregate((a, b) => a + b);
}
static void PrintTree(Tree<int> tree)
{
Console.WriteLine(tree.Value);
foreach (var child in tree.Children)
{
Console.WriteLine(" " + child.Value);
}
}
static int PathSum(Tree<int> leaf)
{
int sum = 0;
var temp = leaf;
while (temp.Parent != null)
{
sum += temp.Value;
temp = temp.Parent;
}
sum += temp.Value;
return sum;
}
private static void FindLongestPath(Tree<int> tree, int depth = 1)
{
if (depth > longestPath)
{
longestPath = depth;
longestPathLeaf = tree;
}
foreach (var child in tree.Children)
{
FindLongestPath(child, depth + 1);
}
}
private static void PrintAllPathsWithSum(Tree<int> tree, int sum)
{
if (sum == pathSum)
{
var path = GetPathValues(tree);
Console.WriteLine(string.Join(" -> ", path));
}
foreach (var child in tree.Children)
{
PrintAllPathsWithSum(child, sum + child.Value);
}
}
private static IEnumerable<int> GetPathValues(Tree<int> tree)
{
var result = new Stack<int>();
while (tree != null)
{
result.Push(tree.Value);
tree = tree.Parent;
}
return result;
}
/// <summary>
/// Finds all paths witch sum is equal to given sum using recursion.
/// </summary>
/// <param name="sum">Sum to be found.</param>
/// <param name="node">Given child for start point.</param>
/// <param name="elements">Current path.</param>
/// <param name="bestElements">All paths equal to the sum.</param>
/// <returns>All paths equal to the sum.</returns>
private List<List<Tree>> FindAllPathsWithGivenSum(int sum, Tree node, List<Tree> elements, List<List<Tree>> bestElements)
{
var children = node.Children;
foreach (var child in children)
{
elements.Add(child);
if (elements.Sum(e => e.Value) == sum)
{
bestElements.Add(elements);
elements = GetElementsSoFar(child);
}
if (child.Children.Count != 0)
{
bestElements = this.FindAllPathsWithGivenSum(sum, child, elements, bestElements);
}
elements = GetElementsSoFar(child);
}
return bestElements;
}
