111 lines
2.2 KiB
Rust
111 lines
2.2 KiB
Rust
/**
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* [173] Binary Search Tree Iterator
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*/
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pub struct Solution {}
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use tokio::time::error::Elapsed;
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use crate::util::tree::{to_tree, TreeNode};
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// submission codes start here
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// Definition for a binary tree node.
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// #[derive(Debug, PartialEq, Eq)]
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// pub struct TreeNode {
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// pub val: i32,
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// pub left: Option<Rc<RefCell<TreeNode>>>,
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// pub right: Option<Rc<RefCell<TreeNode>>>,
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// }
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//
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// impl TreeNode {
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// #[inline]
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// pub fn new(val: i32) -> Self {
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// TreeNode {
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// val,
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// left: None,
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// right: None
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// }
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// }
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// }
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use std::cell::RefCell;
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use std::rc::Rc;
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struct BSTIterator {
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stack: Vec<Rc<RefCell<TreeNode>>>,
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}
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/**
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* `&self` means the method takes an immutable reference.
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* If you need a mutable reference, change it to `&mut self` instead.
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*/
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impl BSTIterator {
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fn new(root: Option<Rc<RefCell<TreeNode>>>) -> Self {
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if root.is_none() {
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return BSTIterator { stack: vec![] };
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}
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let mut stack = vec![];
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let root = root.unwrap();
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let mut node = root;
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loop {
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stack.push(Rc::clone(&node));
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let left = if let Some(left) = &node.borrow().left {
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Rc::clone(left)
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} else {
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break;
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};
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node = left;
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}
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BSTIterator { stack }
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}
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fn next(&mut self) -> i32 {
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let node = self.stack.pop().unwrap();
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let val = node.borrow().val;
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if let Some(right) = &node.borrow().right {
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let mut node = Rc::clone(right);
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loop {
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self.stack.push(Rc::clone(&node));
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let left = if let Some(left) = &node.borrow().left {
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Rc::clone(left)
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} else {
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break;
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};
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node = left;
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}
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}
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val
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}
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fn has_next(&self) -> bool {
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!self.stack.is_empty()
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}
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}
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/**
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* Your BSTIterator object will be instantiated and called as such:
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* let obj = BSTIterator::new(root);
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* let ret_1: i32 = obj.next();
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* let ret_2: bool = obj.has_next();
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*/
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// submission codes end
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_173() {}
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}
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