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feat: update solutions to lcof problems: No.32.1,34 #2875

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merged 1 commit into from
May 22, 2024
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feat: update solutions to lcof problems: No.32.1,34 #2875

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52 changes: 28 additions & 24 deletions lcof/面试题32 - I. 从上到下打印二叉树/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -211,18 +211,21 @@ func levelOrder(root *TreeNode) (ans []int) {
*/

function levelOrder(root: TreeNode | null): number[] {
const res = [];
if (root == null) {
return res;
const ans: number[] = [];
if (!root) {
return ans;
}
const queue = [root];
while (queue.length !== 0) {
const { val, left, right } = queue.shift();
res.push(val);
left && queue.push(left);
right && queue.push(right);
const q: TreeNode[] = [root];
while (q.length) {
const t: TreeNode[] = [];
for (const { val, left, right } of q) {
ans.push(val);
left && t.push(left);
right && t.push(right);
}
q.splice(0, q.length, ...t);
}
return res;
return ans;
}
```

Expand Down Expand Up @@ -252,22 +255,22 @@ use std::cell::RefCell;
use std::collections::VecDeque;
impl Solution {
pub fn level_order(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<i32> {
let mut res = Vec::new();
let mut queue = VecDeque::new();
let mut ans = Vec::new();
let mut q = VecDeque::new();
if let Some(node) = root {
queue.push_back(node);
q.push_back(node);
}
while let Some(node) = queue.pop_front() {
while let Some(node) = q.pop_front() {
let mut node = node.borrow_mut();
res.push(node.val);
ans.push(node.val);
if let Some(l) = node.left.take() {
queue.push_back(l);
q.push_back(l);
}
if let Some(r) = node.right.take() {
queue.push_back(r);
q.push_back(r);
}
}
res
ans
}
}
```
Expand All @@ -287,18 +290,19 @@ impl Solution {
* @return {number[]}
*/
var levelOrder = function (root) {
const ans = [];
if (!root) {
return [];
return ans;
}
const q = [root];
const ans = [];
while (q.length) {
for (let n = q.length; n; --n) {
const { val, left, right } = q.shift();
const t = [];
for (const { val, left, right } of q) {
ans.push(val);
left && q.push(left);
right && q.push(right);
left && t.push(left);
right && t.push(right);
}
q.splice(0, q.length, ...t);
}
return ans;
};
Expand Down
13 changes: 7 additions & 6 deletions lcof/面试题32 - I. 从上到下打印二叉树/Solution.js
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Original file line number Diff line number Diff line change
Expand Up @@ -10,18 +10,19 @@
* @return {number[]}
*/
var levelOrder = function (root) {
const ans = [];
if (!root) {
return [];
return ans;
}
const q = [root];
const ans = [];
while (q.length) {
for (let n = q.length; n; --n) {
const { val, left, right } = q.shift();
const t = [];
for (const { val, left, right } of q) {
ans.push(val);
left && q.push(left);
right && q.push(right);
left && t.push(left);
right && t.push(right);
}
q.splice(0, q.length, ...t);
}
return ans;
};
16 changes: 8 additions & 8 deletions lcof/面试题32 - I. 从上到下打印二叉树/Solution.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,21 +21,21 @@ use std::cell::RefCell;
use std::collections::VecDeque;
impl Solution {
pub fn level_order(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<i32> {
let mut res = Vec::new();
let mut queue = VecDeque::new();
let mut ans = Vec::new();
let mut q = VecDeque::new();
if let Some(node) = root {
queue.push_back(node);
q.push_back(node);
}
while let Some(node) = queue.pop_front() {
while let Some(node) = q.pop_front() {
let mut node = node.borrow_mut();
res.push(node.val);
ans.push(node.val);
if let Some(l) = node.left.take() {
queue.push_back(l);
q.push_back(l);
}
if let Some(r) = node.right.take() {
queue.push_back(r);
q.push_back(r);
}
}
res
ans
}
}
23 changes: 13 additions & 10 deletions lcof/面试题32 - I. 从上到下打印二叉树/Solution.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -13,16 +13,19 @@
*/

function levelOrder(root: TreeNode | null): number[] {
const res = [];
if (root == null) {
return res;
const ans: number[] = [];
if (!root) {
return ans;
}
const queue = [root];
while (queue.length !== 0) {
const { val, left, right } = queue.shift();
res.push(val);
left && queue.push(left);
right && queue.push(right);
const q: TreeNode[] = [root];
while (q.length) {
const t: TreeNode[] = [];
for (const { val, left, right } of q) {
ans.push(val);
left && t.push(left);
right && t.push(right);
}
q.splice(0, q.length, ...t);
}
return res;
return ans;
}
139 changes: 33 additions & 106 deletions lcof/面试题34. 二叉树中和为某一值的路径/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -228,26 +228,26 @@ func pathSum(root *TreeNode, target int) (ans [][]int) {
*/

function pathSum(root: TreeNode | null, target: number): number[][] {
const res: number[][] = [];
if (root == null) {
return res;
}
const paths: number[] = [];
const dfs = ({ val, right, left }: TreeNode, target: number) => {
paths.push(val);
target -= val;
if (left == null && right == null) {
if (target === 0) {
res.push([...paths]);
}
} else {
left && dfs(left, target);
right && dfs(right, target);
const ans: number[][] = [];
const t: number[] = [];

const dfs = (root: TreeNode | null, s: number): void => {
if (!root) {
return;
}
const { val, left, right } = root;
t.push(val);
s -= val;
if (!left && !right && s === 0) {
ans.push([...t]);
}
paths.pop();
dfs(left, s);
dfs(right, s);
t.pop();
};

dfs(root, target);
return res;
return ans;
}
```

Expand Down Expand Up @@ -278,26 +278,26 @@ impl Solution {
fn dfs(
root: &Option<Rc<RefCell<TreeNode>>>,
mut target: i32,
paths: &mut Vec<i32>,
res: &mut Vec<Vec<i32>>
t: &mut Vec<i32>,
ans: &mut Vec<Vec<i32>>
) {
if let Some(node) = root.as_ref() {
let node = node.borrow();
paths.push(node.val);
t.push(node.val);
target -= node.val;
if node.left.is_none() && node.right.is_none() && target == 0 {
res.push(paths.clone());
ans.push(t.clone());
}
Self::dfs(&node.left, target, paths, res);
Self::dfs(&node.right, target, paths, res);
paths.pop();
Self::dfs(&node.left, target, t, ans);
Self::dfs(&node.right, target, t, ans);
t.pop();
}
}

pub fn path_sum(root: Option<Rc<RefCell<TreeNode>>>, target: i32) -> Vec<Vec<i32>> {
let mut res = vec![];
Self::dfs(&root, target, &mut vec![], &mut res);
res
let mut ans = vec![];
Self::dfs(&root, target, &mut vec![], &mut ans);
ans
}
}
```
Expand Down Expand Up @@ -325,13 +325,14 @@ var pathSum = function (root, target) {
if (!root) {
return;
}
t.push(root.val);
s -= root.val;
if (!root.left && !root.right && !s) {
const { val, left, right } = root;
t.push(val);
s -= val;
if (!left && !right && !s) {
ans.push([...t]);
}
dfs(root.left, s);
dfs(root.right, s);
dfs(left, s);
dfs(right, s);
t.pop();
};
dfs(root, target);
Expand Down Expand Up @@ -384,78 +385,4 @@ public class Solution {

<!-- solution:end -->

<!-- solution:start-->

### 方法二

<!-- tabs:start -->

#### Rust

```rust
// 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::rc::Rc;
use std::cell::RefCell;
impl Solution {
fn dfs(
root: &Option<Rc<RefCell<TreeNode>>>,
mut target: i32,
paths: &mut Vec<i32>
) -> Vec<Vec<i32>> {
let node = root.as_ref().unwrap().borrow();
paths.push(node.val);
target -= node.val;
let mut res = vec![];
// 确定叶结点身份
if node.left.is_none() && node.right.is_none() {
if target == 0 {
res.push(paths.clone());
}
} else {
if node.left.is_some() {
let res_l = Self::dfs(&node.left, target, paths);
if !res_l.is_empty() {
res = [res, res_l].concat();
}
}
if node.right.is_some() {
let res_r = Self::dfs(&node.right, target, paths);
if !res_r.is_empty() {
res = [res, res_r].concat();
}
}
}
paths.pop();
res
}
pub fn path_sum(root: Option<Rc<RefCell<TreeNode>>>, target: i32) -> Vec<Vec<i32>> {
if root.is_none() {
return vec![];
}
Self::dfs(&root, target, &mut vec![])
}
}
```

<!-- tabs:end -->

<!-- solution:end -->

<!-- problem:end -->
11 changes: 6 additions & 5 deletions lcof/面试题34. 二叉树中和为某一值的路径/Solution.js
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,13 +18,14 @@ var pathSum = function (root, target) {
if (!root) {
return;
}
t.push(root.val);
s -= root.val;
if (!root.left && !root.right && !s) {
const { val, left, right } = root;
t.push(val);
s -= val;
if (!left && !right && !s) {
ans.push([...t]);
}
dfs(root.left, s);
dfs(root.right, s);
dfs(left, s);
dfs(right, s);
t.pop();
};
dfs(root, target);
Expand Down
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