diff --git a/problems/0102.二叉树的层序遍历.md b/problems/0102.二叉树的层序遍历.md index 3a4e0a31..1a01c0ae 100644 --- a/problems/0102.二叉树的层序遍历.md +++ b/problems/0102.二叉树的层序遍历.md @@ -380,29 +380,32 @@ object Solution { Rust: ```rust -pub fn level_order(root: Option>>) -> Vec> { - let mut ans = Vec::new(); - let mut stack = Vec::new(); - if root.is_none(){ - return ans; - } - stack.push(root.unwrap()); - while stack.is_empty()!= true{ - let num = stack.len(); - let mut level = Vec::new(); - for _i in 0..num{ - let tmp = stack.remove(0); - level.push(tmp.borrow_mut().val); - if tmp.borrow_mut().left.is_some(){ - stack.push(tmp.borrow_mut().left.take().unwrap()); - } - if tmp.borrow_mut().right.is_some(){ - stack.push(tmp.borrow_mut().right.take().unwrap()); - } +use std::cell::RefCell; +use std::rc::Rc; +use std::collections::VecDeque; +impl Solution { + pub fn level_order(root: Option>>) -> Vec> { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); } - ans.push(level); + while !queue.is_empty() { + let mut temp = vec![]; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + temp.push(node.borrow().val); + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + res.push(temp); + } + res } - ans } ``` @@ -665,29 +668,32 @@ object Solution { Rust: ```rust -pub fn level_order(root: Option>>) -> Vec> { - let mut ans = Vec::new(); - let mut stack = Vec::new(); - if root.is_none(){ - return ans; - } - stack.push(root.unwrap()); - while stack.is_empty()!= true{ - let num = stack.len(); - let mut level = Vec::new(); - for _i in 0..num{ - let tmp = stack.remove(0); - level.push(tmp.borrow_mut().val); - if tmp.borrow_mut().left.is_some(){ - stack.push(tmp.borrow_mut().left.take().unwrap()); - } - if tmp.borrow_mut().right.is_some(){ - stack.push(tmp.borrow_mut().right.take().unwrap()); - } +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn level_order_bottom(root: Option>>) -> Vec> { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); } - ans.push(level); + while !queue.is_empty() { + let mut temp = vec![]; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + temp.push(node.borrow().val); + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + res.push(temp); + } + res.into_iter().rev().collect() } - ans } ``` @@ -935,6 +941,39 @@ object Solution { } ``` +rust: + +```rust +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn right_side_view(root: Option>>) -> Vec { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + let len = queue.len(); + for i in 0..len { + let node = queue.pop_front().unwrap().unwrap(); + if i == len - 1 { + res.push(node.borrow().val); + } + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + } + res + } +} +``` + # 637.二叉树的层平均值 [力扣题目链接](https://leetcode.cn/problems/average-of-levels-in-binary-tree/) @@ -1185,6 +1224,39 @@ object Solution { } ``` +rust: + +```rust +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn average_of_levels(root: Option>>) -> Vec { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + let len = queue.len(); + let mut sum = 0; + for _ in 0..len { + let node = queue.pop_front().unwrap().unwrap(); + sum += node.borrow().val; + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + res.push((sum as f64) / len as f64); + } + res + } +} +``` + # 429.N叉树的层序遍历 [力扣题目链接](https://leetcode.cn/problems/n-ary-tree-level-order-traversal/) @@ -1456,6 +1528,54 @@ object Solution { } ``` +rust: + +```rust +pub struct Solution; +#[derive(Debug, PartialEq, Eq)] +pub struct Node { + pub val: i32, + pub children: Vec>>>, +} + +impl Node { + #[inline] + pub fn new(val: i32) -> Node { + Node { + val, + children: vec![], + } + } +} + +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn level_order(root: Option>>) -> Vec> { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + let mut temp = vec![]; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + temp.push(node.borrow().val); + if !node.borrow().children.is_empty() { + for n in node.borrow().children.clone() { + queue.push_back(n); + } + } + } + res.push(temp) + } + res + } +} +``` + # 515.在每个树行中找最大值 [力扣题目链接](https://leetcode.cn/problems/find-largest-value-in-each-tree-row/) @@ -1686,6 +1806,38 @@ object Solution { } ``` +rust: + +```rust +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn largest_values(root: Option>>) -> Vec { + let mut res = vec![]; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + let mut max = i32::MIN; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + max = max.max(node.borrow().val); + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + res.push(max); + } + res + } +} +``` + # 116.填充每个节点的下一个右侧节点指针 [力扣题目链接](https://leetcode.cn/problems/populating-next-right-pointers-in-each-node/) @@ -2472,6 +2624,36 @@ object Solution { } ``` +rust: + +```rust +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn max_depth(root: Option>>) -> i32 { + let mut queue = VecDeque::new(); + let mut res = 0; + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + res += 1; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + } + res + } +} +``` + # 111.二叉树的最小深度 [力扣题目链接](https://leetcode.cn/problems/minimum-depth-of-binary-tree/) @@ -2716,6 +2898,39 @@ object Solution { } ``` +rust: + +```rust +use std::cell::RefCell; +use std::collections::VecDeque; +use std::rc::Rc; +impl Solution { + pub fn min_depth(root: Option>>) -> i32 { + let mut res = 0; + let mut queue = VecDeque::new(); + if root.is_some() { + queue.push_back(root); + } + while !queue.is_empty() { + res += 1; + for _ in 0..queue.len() { + let node = queue.pop_front().unwrap().unwrap(); + if node.borrow().left.is_none() && node.borrow().right.is_none() { + return res; + } + if node.borrow().left.is_some() { + queue.push_back(node.borrow().left.clone()); + } + if node.borrow().right.is_some() { + queue.push_back(node.borrow().right.clone()); + } + } + } + res + } +} +``` + # 总结 二叉树的层序遍历,**就是图论中的广度优先搜索在二叉树中的应用**,需要借助队列来实现(此时又发现队列的一个应用了)。