//is node n present in tree/subtree rooted at node tree
int IsNodeInTree(struct btnode* tree, struct btnode* n)
{
if(tree==NULL)
return 0;
if(tree==n)
return 1;
return IsNodeInTree(tree->l,n)||IsNodeInTree(tree->r,n);
}
//checking common ancestor of two nodes a and b
struct btnode* common_ancestor(struct btnode * tree,struct btnode * a, struct btnode * b)
{
struct btnode * temp;
if(IsNodeInTree(tree,a) ==1 && IsNodeInTree(tree,b)==1)
{
if((IsNodeInTree(tree->l,a) ==1 && IsNodeInTree(tree->r,b)==1)||IsNodeInTree(tree->r,a)==1 && IsNodeInTree(tree->l,b)==1)
{
return tree;
}
else if(IsNodeInTree(tree->l,a) ==1 && IsNodeInTree(tree->l,b)==1)
{
temp=common_ancestor(tree->l,a,b);
return temp;
}
else if(IsNodeInTree(tree->r,a) ==1 && IsNodeInTree(tree->r,b)==1)
{
temp=common_ancestor(tree->r,a,b);
return temp;
}
}
else
{
return NULL;
}
}
bool Tree::IsNodeInTree(TreeNode *nodeToFind, TreeNode *nodeToInspect)
{
if(nodeToInspect == NULL)
return false;
if(nodeToInspect->_value == nodeToFind->_value)
return true;
if(nodeToFind->_value < nodeToInspect->_value)
{
return IsNodeInTree(nodeToFind, nodeToInspect->_left);
} else {
return IsNodeInTree(nodeToFind, nodeToInspect->_right);
}
}
int main()
{
struct btnode *one,*two,*three,*four,*five,*six,*seven,*temp;
one=initNode(1);
two=initNode(2);
three=initNode(3);
four=initNode(4);
five=initNode(5);
six=initNode(6);
root=one;
//one node outside tree
seven=initNode(7);
//set the tree
one->l=two;
one->r=three;
three->l=four;
three->r=six;
four->l=five;
//Checking if node belongs to the tree
printf("node four in tree:%d\n",IsNodeInTree(root,four));
printf("node six in tree:%d\n",IsNodeInTree(root,six));
//checking what is common ancestor of node 5 and 6
temp=common_ancestor(root,five,six);
if(temp != NULL)
{
printf("Common ancestor of 5 and 6 is:%d\n",temp->val);
}
else
printf("Common ancestor does not exist!\n");
//checking what is common ancestor of node 3 and 7
temp=common_ancestor(root,three,seven);
if(temp != NULL)
{
printf("Common ancestor of 3 and 7 is:%d\n",temp->val);
}
else
printf("Common ancestor does not exist!\n");
}
bool Tree::IsNodeInTree(TreeNode *nodeToFind)
{
return IsNodeInTree(nodeToFind, _rootNode);
}
bool Tree::IsNodeInTree(int value)
{
TreeNode node(value);
return IsNodeInTree(&node, _rootNode);
}
