Binary Trees VS Hash Tables

For what purpose binary trees are preferred over hash tables?

What are hash tables and Binary trees?

Arrays and Linked Lists

What are arrays and linked lists. In what situation linked lists are prefered over arrays.

Binary Tree Question

Write a function which takes a binary tree. Return false if any node other than the leaf nodes have less than 2 nodes. Write test cases

Palindrome using data structure

Implement a palindrome using any data structure (complexity - logn)

Binary Search Tree .. look inside for more details

Insert a node to a Binary Search Tree and test the function. Take an example and walk through the code. If you were to balance the tree, what would the coding logic be?

How to find if linked list is circular or not?

Any answers?


********************************************

Have 2 pointers .. one is slow and the other is fast (fast pointer moves twice whereas slow pointer moves once) .. if the list is circular both the pointers will meet meet.

bool findCircular(Node *head)
{
Node *slower, * faster;
slower = head;
faster = head;
while(true) {

// if the faster pointer encounters a NULL element
if( !faster || !faster->next)
return false;
//if faster pointer ever equals slower or faster's next
//pointer is ever equal to slow then it's a circular list
else if (faster == slower || faster->next == slower)
return true;
else{
// advance the pointers
slower = slower->next;
faster = faster->next->next;
}
}
}