//Given is the list of node and it has parent, value and weight
//To calculate total weight of the subtree we need to know the parent and child relation that is Parent and List<children>
//we can either use ht to build the structure or modify the node to have this property
//Find the root of the tree
//And then use DFS to find the tree's weight..go to children first and then sibling
private void PrintSubTreeWeight(List <NodeWithWeight> nodes)
{
//Build ht with key as parent and value as list of children
Dictionary <NodeWithWeight, List <NodeWithWeight> > htparentchild = new Dictionary <NodeWithWeight, List <NodeWithWeight> >();
//Build another ht with key as childnode and value as parent ..this is used to find the root
//we can use childparent map to find the root but here since we already loop through the nodes, we can find the root without the use of this ht
//Dictionary<NodeWithWeight, NodeWithWeight> htchildparentmap = new Dictionary<NodeWithWeight, NodeWithWeight>();
NodeWithWeight root = null;
foreach (NodeWithWeight node in nodes)
{
//we have to build parent and list of chilren
if (node.Parent != null)
{
if (!htparentchild.ContainsKey(node.Parent))
{
htparentchild.Add(node.Parent, new List <NodeWithWeight>());
}
htparentchild[node.Parent].Add(node);
}
else
{
root = node;
}
}
//void function that set the weight prop of the tree //test get the root weight
int result = CalculateTreeWeight(root, htparentchild);
}
private void button11_Click(object sender, EventArgs e)
{
//List of Nodes
//http://www.careercup.com/question?id=5648527329853440
//id,parent,weight
//10,30,1
//30,0,10
//20,30,2
//50,40,3
//40,30,4
//we parse the given input using ht and get the structure of the tree like this
// 0
// 30
// 10 20 40
// 50
NodeWithWeight node0 = new NodeWithWeight(0, 0);
NodeWithWeight node30 = new NodeWithWeight(30, 10);
NodeWithWeight node10 = new NodeWithWeight(10, 1);
NodeWithWeight node20 = new NodeWithWeight(20, 2);
NodeWithWeight node40 = new NodeWithWeight(40, 4);
NodeWithWeight node50 = new NodeWithWeight(50, 3);
node30.Parent = node0;
node10.Parent = node30;
node20.Parent = node30;
node40.Parent = node30;
node50.Parent = node40;
List <NodeWithWeight> nodes = new List <NodeWithWeight>();
nodes.Add(node0);
nodes.Add(node30);
nodes.Add(node10);
nodes.Add(node20);
nodes.Add(node40);
nodes.Add(node50);
PrintSubTreeWeight2(nodes);
}
//Given is the list of node and it has parent, value and weight
//To calculate total weight of the subtree we need to know the parent and child relation that is Parent and List<children>
//we can either use ht to build the structure or modify the node to have this property
//Find the root of the tree
//And then use DFS to find the tree's weight..go to children first and then sibling
private void PrintSubTreeWeight2(List <NodeWithWeight> nodes)
{
NodeWithWeight root = null;
//Change the structure of the tree to have list<childre>
foreach (NodeWithWeight node in nodes)
{
if (node.Parent != null)
{
node.Parent.Childs.Add(node);
}
else
{
root = node;
}
}
int totalweight = CalculateTreeWeight(root);
}
private int CalculateTreeWeight(NodeWithWeight root)
{
if (root == null)
{
return(0);
}
int Weight = root.Weight;
//get the weight of the subtrees
if (root.Childs.Count > 0)
{
foreach (NodeWithWeight child in root.Childs)
{
Weight += CalculateTreeWeight(child);
}
}
//set the prop of the tree
root.TreeWeight = Weight;
return(Weight);
}
private int CalculateTreeWeight(NodeWithWeight root, Dictionary <NodeWithWeight, List <NodeWithWeight> > htparentchild)
{
if (root == null)
{
return(0);
}
int Weight = root.Weight;
//get the weight of the subtrees
if (htparentchild.ContainsKey(root))
{
List <NodeWithWeight> childrens = htparentchild[root];
foreach (NodeWithWeight child in childrens)
{
Weight += CalculateTreeWeight(child, htparentchild);
}
}
//set the prop of the tree
root.TreeWeight = Weight;
return(Weight);
}
