binary-search-tree-iterator.rs

#![allow(dead_code, unused, unused_variables)]

fnmain(){}

structSolution;

// Definition for a binary tree node.
#[derive(Debug,PartialEq,Eq)]
pubstructTreeNode{
pubval:i32,
publeft:Option<Rc<RefCell<TreeNode>>>,
pubright:Option<Rc<RefCell<TreeNode>>>,
}

implTreeNode{
#[inline]
pubfnnew(val:i32) -> Self{
TreeNode{
 val,
left:None,
right:None,
}
}
}

use std::cell::RefCell;
use std::rc::Rc;

/**
 * Your BSTIterator object will be instantiated and called as such:
 * let obj = BSTIterator::new(root);
 * let ret_1: i32 = obj.next();
 * let ret_2: bool = obj.has_next();
 */
structBSTIterator{
stack:Vec<Option<Rc<RefCell<TreeNode>>>>,
}

/**
 * `&self` means the method takes an immutable reference.
 * If you need a mutable reference, change it to `&mut self` instead.
 */
implBSTIterator{
fnnew(root:Option<Rc<RefCell<TreeNode>>>) -> Self{
letmut s = Self{stack:vec![]};
if root.is_some(){
 s.stack.push(root);
}
 s
}

fnnext(&mutself) -> i32{
letmut node = self.stack.pop().unwrap();

while node.is_some(){
let s = node;
let left = s.as_ref().unwrap().borrow_mut().left.take();
let right = s.as_ref().unwrap().borrow_mut().right.take();

if right.is_some(){
self.stack.push(right);
}

self.stack.push(s);
 node = left;
}

let r = self.stack.pop().unwrap().as_ref().unwrap().borrow().val;
 r
}

fnhas_next(&self) -> bool{
self.stack.len() > 0
}
}