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043_BSTIterator.cpp
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043_BSTIterator.cpp
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#include<bits/stdc++.h>
using namespace std;
/************************************************************
Following is the TreeNode class structure
************************************************************/
template <typename T>
class TreeNode {
public:
T data;
TreeNode<T> *left;
TreeNode<T> *right;
TreeNode(T data) {
this->data = data;
left = NULL;
right = NULL;
}
};
class BSTiterator
{
public:
stack<TreeNode<int> *> S;
BSTiterator(TreeNode<int> *root)
{
// write your code here
add(root);
}
void add(TreeNode<int> *root){
if(!root) return;
while(root){
S.push(root);
root=root->left;
}
}
int next()
{
// write your code here
if(S.empty()){
return -1;
}
TreeNode<int> *root=S.top();
S.pop();
int data=root->data;
add(root->right);
return data;
}
bool hasNext()
{
// write your code here
return !S.empty();
}
};
/*
Your BSTIterator object will be instantiated and called as such:
BSTIterator iterator(root);
while(iterator.hasNext())
{
print(iterator.next());
}
*/