20240221 Finsihed

This commit is contained in:
jackfiled 2024-02-21 21:19:54 +08:00
parent 80567e660e
commit 6834721bd6
2 changed files with 100 additions and 1 deletions

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@ -50,4 +50,5 @@ mod p987_vertical_order_traversal_of_a_binary_tree;
mod p102_binary_tree_level_order_traversal;
mod p107_binary_tree_level_order_traversal_ii;
mod p103_binary_tree_zigzag_level_order_traversal;
mod p105_construct_binary_tree_from_preorder_and_inorder_traversal;
mod p105_construct_binary_tree_from_preorder_and_inorder_traversal;
mod p106_construct_binary_tree_from_inorder_and_postorder_traversal;

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@ -0,0 +1,98 @@
/**
* [106] Construct Binary Tree from Inorder and Postorder Traversal
*/
pub struct Solution {}
use crate::util::tree::{to_tree, TreeNode};
// submission codes start here
// Definition for a binary tree node.
// #[derive(Debug, PartialEq, Eq)]
// pub struct TreeNode {
// pub val: i32,
// pub left: Option<Rc<RefCell<TreeNode>>>,
// pub right: Option<Rc<RefCell<TreeNode>>>,
// }
//
// impl TreeNode {
// #[inline]
// pub fn new(val: i32) -> Self {
// TreeNode {
// val,
// left: None,
// right: None
// }
// }
// }
use std::cell::RefCell;
use std::rc::Rc;
impl Solution {
pub fn build_tree(inorder: Vec<i32>, postorder: Vec<i32>) -> Option<Rc<RefCell<TreeNode>>> {
if inorder.len() == 0 {
return None;
}
let root = Rc::new(RefCell::new(TreeNode::new(postorder[postorder.len() - 1])));
let mut stack = Vec::new();
stack.push(Rc::clone(&root));
let mut inorder_index = inorder.len() - 1;
for i in (0..postorder.len() - 1).rev() {
let post_order_value = postorder[i];
let mut node = Rc::clone(stack.last().unwrap());
if node.borrow().val != inorder[inorder_index] {
let new_node = Rc::new(RefCell::new(TreeNode::new(post_order_value)));
stack.push(Rc::clone(&new_node));
node.borrow_mut().right = Some(new_node);
} else {
while let Some(top) = stack.last() {
if top.borrow().val == inorder[inorder_index] {
node = Rc::clone(top);
stack.pop();
inorder_index -= 1;
} else {
break;
}
}
let new_node = Rc::new(RefCell::new(TreeNode::new(post_order_value)));
stack.push(Rc::clone(&new_node));
node.borrow_mut().left = Some(new_node);
}
}
Some(root)
}
}
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_106() {
assert_eq!(
Solution::build_tree(vec![9, 3, 15, 20, 7], vec![9, 15, 7, 20, 3]),
to_tree(vec![
Some(3),
Some(9),
Some(20),
None,
None,
Some(15),
Some(7)
])
);
assert_eq!(
Solution::build_tree(vec![-1], vec![-1]),
to_tree(vec![Some(-1)])
);
}
}