Hi, The idea is like this:
Isbst(node *t){ if(t==NULL){ return true; } if ( Isbst(t->left) && Isbst(t->right) && (maxValue(t->left) <=(t->data) ) && (minValue(t->right) >= (t->data) ) return true; else return false; } I hope it makes sense :D On Thu, Jul 1, 2010 at 3:37 PM, vicky <mehta...@gmail.com> wrote: > just do one thing print inorder. if sorted it is a BST > > On Jun 19, 2:57 pm, divya <sweetdivya....@gmail.com> wrote: > > i have found the following code on net to check if the binarytreeis > > bst or not > > /* > > Returns true if a binarytreeis a binary searchtree. > > */ > > int isBST(struct node* node) { > > if (node==NULL) return(true); > > // false if the min of the left is > than us > > if (node->left!=NULL && minValue(node->left) > node->data) > > return(false); > > // false if the max of the right is <= than us > > if (node->right!=NULL && maxValue(node->right) <= node->data) > > return(false); > > // false if, recursively, the left or right is not a BST > > if (!isBST(node->left) || !isBST(node->right)) > > return(false); > > // passing all that, it's a BST > > return(true); > > > > } > > > > int minValue(struct node* node) { > > struct node* current = node; > > // loop down to find the leftmost leaf > > while (current->left != NULL) { > > current = current->left;} > > > > return(current->data); > > > > } > > > > and maxvalue also similarly returns right most vaslue oftree.. > > > > now i have a doubt that here v r comparing the node->data with only > > the min node nd max node.. shd nt we compare the node data with its > > left node and right node only. > > as it can b a case that node value is greater than min but less than > > its left node.. nd here we r nt checking that... > > > > plzzzzzz correct me if i m wrong........... > > > > and is there any other efficient method to find isbst? > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algoge...@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algoge...@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.