89 lines
1.9 KiB
Rust
89 lines
1.9 KiB
Rust
/**
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* [102] Binary Tree Level Order Traversal
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*/
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pub struct Solution {}
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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::collections::VecDeque;
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use std::rc::Rc;
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impl Solution {
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pub fn level_order(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<Vec<i32>> {
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let root = if let Some(r) = root {
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r
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} else {
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return vec![];
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};
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let mut result = Vec::new();
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let mut queue = VecDeque::new();
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queue.push_back(root);
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while !queue.is_empty() {
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let mut level = Vec::with_capacity(queue.len());
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for _ in 0..queue.len() {
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if let Some(node) = queue.pop_front() {
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level.push(node.borrow().val);
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if let Some(left) = &node.borrow().left {
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queue.push_back(Rc::clone(left));
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}
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if let Some(right) = &node.borrow().right {
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queue.push_back(Rc::clone(right));
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}
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}
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}
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result.push(level);
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}
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result
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}
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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_102() {
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assert_eq!(
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Solution::level_order(to_tree(vec![
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Some(3),
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Some(9),
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Some(20),
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None,
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None,
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Some(15),
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Some(7)
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])),
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vec![vec![3], vec![9, 20], vec![15, 7]]
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);
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}
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}
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