Interview Practice Basic – Breathe First Traversal

In the iterative way You can only do breathe first traversal in iterative way. Though you can still make it recursive by calling itself in each loop, but you will not benefit from it. It is similar to doing depth first traversal, instead you use a FIFO queue to store the nodes. Node definition static…

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Interview Practice Basic – Depth First Traversal

There are 4 ways to do a depth first traversal, depends on how you would like to do it.

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Interview Practice Extra 07 – Universal Value Binary Tree

Question Design an algorithm to verify that a tree is a universal value binary tree. Universal value binary tree means all value in that tree is the same. Solution There is two approach for this problem. One is with recursive function and another is with iterative function. For this problem, iterative function makes simpler answer. However,…

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Interview Practice Extra 03 – Verify Binary Tree with Same Value

Question Verify whether all nodes have the same value in a binary tree. Solution We can traverse the tree with our usual way, like depth-first or breadth-first algorithm. Then pass a value, probably the root value, to compare with the visiting node. Example # node structure class bst_node: value = None left = None right…

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Interview Practice 16 – Print Binary Tree Layer-by-layer

Question Print a binary tree layer-by-layer from top to bottom, and from left to right for each layer. Solution Yes, it’s a simple task. We can use breadth-first search, and which means we need a queue, see reference. levelorder(root) q = empty queue q.enqueue(root) while not q.empty do node := q.dequeue() visit(node) if node.left ≠…

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Interview Practice 15 – Mirror Image of Binary Tree

Question Construct 2 algorithms to make mirror image of any binary tree inputs, one of them using recursive method, another one using looping method. Mirror image means a binary tree that is the horizontal reflection of the original tree. Solution First, to do it in recursive method, we can perform pre-order traversal as usual, see preference….

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Interview Practice 11 – Greatest Distance Between Two Nodes in Binary Tree

Get the greatest distance between two nodes in a binary tree. Assume links between nodes are bidirectional. Distance is defined as the amount of nodes connected along the path linked two nodes.

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Interview Practice 09 – Verify Post-order Sequence of BST

Construct an algorithm to verify if a set of numbers is the post-order search result of a binary search tree.

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Interview Practice 01 – Convert Binary Tree into Doubly Linked List

Question Convert binary search tree into doubly linked list. It’s required not to create any new node, but only turning pointers. Solution The following shows the concept of this question. 8 / 6 0 -> 5 = 6 = 7 = 8 = 9 = 0 = 1 / / 5 7 9 1 First,…

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Ssh with password saved

Ssh is a very convenient way to remotely command or control other devices. We use ssh to push commits to git server, to access remote server, and even to manipulate the content of our iphones and ipads. However it’s usually distributing to type your long and elusive password every time. Therefore here I would like…

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