problem0173

README

173. Binary Search Tree Iterator

Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST.

Calling next() will return the next smallest number in the BST.

Example:

BSTIterator iterator = new BSTIterator(root);
iterator.next();    // return 3
iterator.next();    // return 7
iterator.hasNext(); // return true
iterator.next();    // return 9
iterator.hasNext(); // return true
iterator.next();    // return 15
iterator.hasNext(); // return true
iterator.next();    // return 20
iterator.hasNext(); // return false

Note:

• next() and hasNext() should run in average O(1) time and uses O(h) memory, where h is the height of the tree.
• You may assume that next() call will always be valid, that is, there will be at least a next smallest number in the BST when next() is called.

Documentation

Index

• type BSTIterator
  • func Constructor(root *TreeNode) BSTIterator
  • func (it *BSTIterator) HasNext() bool
  • func (it *BSTIterator) Next() int
• type TreeNode

Types

type BSTIterator

type BSTIterator struct {
	// contains filtered or unexported fields
}

BSTIterator is the iterator of BST

func Constructor

func Constructor(root *TreeNode) BSTIterator

Constructor returns a BST iterator

func (*BSTIterator) HasNext

func (it *BSTIterator) HasNext() bool

HasNext returns whether we have a next smallest number

func (*BSTIterator) Next

func (it *BSTIterator) Next() int

Next returns the next smallest number

type TreeNode

type TreeNode = kit.TreeNode

TreeNode is pre-defined...

Definition for a binary tree node.
* type TreeNode struct {
*     Val int
*     Left *TreeNode
*     Right *TreeNode
* }