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Cs Summary Reflection

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README-en.md
浏览文件 @ aed4a1f3
......@@ -6,8 +6,8 @@
[![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=jxnu-liguobin_cs-summary-reflection&metric=security_rating)](https://sonarcloud.io/dashboard?id=jxnu-liguobin_cs-summary-reflection)
[![](https://img.shields.io/github/languages/count/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/github/languages/top/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/alerts/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/grade/python/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/alerts/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/alerts/?mode=list)
[![](https://img.shields.io/lgtm/grade/python/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/context:python)
[![Language grade: Java](https://img.shields.io/lgtm/grade/java/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/context:java)
[![](https://img.shields.io/github/commit-activity/m/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/github/contributors-anon/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
......@@ -15,7 +15,7 @@
![](https://img.shields.io/badge/QQ%20Group-655462259-blue.svg?style=social&logo=tencent-qq)
[![Gitter](https://badges.gitter.im/jxnu-liguobin/cs-summary-reflection.svg)](https://gitter.im/jxnu-liguobin/cs-summary-reflection?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
[中文](https://github.com/jxnu-liguobin/cs-summary-reflection/blob/master/README.md) | English
[中文](./README.md) | English
# Leetcode teamed up
......
README.md
浏览文件 @ aed4a1f3
......@@ -6,8 +6,8 @@
[![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=jxnu-liguobin_cs-summary-reflection&metric=security_rating)](https://sonarcloud.io/dashboard?id=jxnu-liguobin_cs-summary-reflection)
[![](https://img.shields.io/github/languages/count/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/github/languages/top/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/alerts/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/grade/python/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://dreamylost.cn)
[![](https://img.shields.io/lgtm/alerts/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/alerts/?mode=list)
[![](https://img.shields.io/lgtm/grade/python/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/context:python)
[![Language grade: Java](https://img.shields.io/lgtm/grade/java/g/jxnu-liguobin/cs-summary-reflection.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/jxnu-liguobin/cs-summary-reflection/context:java)
[![](https://img.shields.io/github/commit-activity/m/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
[![](https://img.shields.io/github/contributors-anon/jxnu-liguobin/cs-summary-reflection)](https://dreamylost.cn)
......@@ -15,7 +15,7 @@
![](https://img.shields.io/badge/QQ%20Group-655462259-blue.svg?style=social&logo=tencent-qq)
[![Gitter](https://badges.gitter.im/jxnu-liguobin/cs-summary-reflection.svg)](https://gitter.im/jxnu-liguobin/cs-summary-reflection?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
中文 | [English](https://github.com/jxnu-liguobin/cs-summary-reflection/blob/master/README-en.md)
中文 | [English](./README-en.md)
# Leetcode 组队刷题
......
java-leetcode/src/main/java/io/github/wkk/everyday/aug/RecoverBinarySearchTree.java 0 → 100644
浏览文件 @ aed4a1f3
/* All Contributors (C) 2020 */
package io.github.wkk.everyday.aug;
import io.github.wkk.structs.TreeNode;
import java.util.ArrayDeque;
import java.util.Deque;
/**
* 恢复二叉搜索树
*
* <p>难点: 找出真正出问题的两个点
*
* <p>思路: 根据其性质, 使用中序遍历, 标记出真正出现问题的两个位置, 之后交换其元素值即可
*
* <p>抽象: .....errorOne |increasing sequence | errorTwo .......
*
* <p>第一个节点,是第一个按照中序遍历时候前一个节点大于后一个节点,我们选取前一个节点
*
* <p>第二个节点,是在第一个节点找到之后, 后面出现前一个节点大于后一个节点,我们选择后一个节点
*
* @author kongwiki@163.com
* @since 2020/8/8上午8:59
*/
public class RecoverBinarySearchTree {
private TreeNode errorOne, errorTwo;
public void recoverTree(TreeNode root) {
helper(root);
swap(errorOne, errorTwo);
}
private void helper(TreeNode root) {
if (root == null) {
return;
}
TreeNode pre = null;
Deque<TreeNode> stack = new ArrayDeque<>();
TreeNode p = root;
while (!stack.isEmpty() || p != null) {
if (p != null) {
stack.push(p);
p = p.left;
} else {
p = stack.pop();
if (pre != null && pre.val > p.val) {
if (errorOne == null) {
errorOne = pre;
errorTwo = p;
} else {
errorTwo = p;
}
}
pre = p;
p = p.right;
}
}
}
private void swap(TreeNode first, TreeNode second) {
int temp = first.val;
first.val = second.val;
second.val = temp;
}
}
java-leetcode/src/main/java/io/github/wkk/everyday/aug/RestoreIPAddresses.java 0 → 100644
浏览文件 @ aed4a1f3
/* All Contributors (C) 2020 */
package io.github.wkk.everyday.aug;
import java.util.ArrayList;
import java.util.List;
/**
* 复原IP地址(IP格式: 每一位都在0-255之间)
*
* <p>思路: 1.暴力求解 2.回溯(涉及到求所有的结果, 常用方法)
*
* @author kongwiki@163.com
* @since 2020/8/9上午9:33
*/
public class RestoreIPAddresses {
/** 暴力求解 需要一个辅助方法, 判断每个子串是否符合IP格式 1. 每位在0-255之间 2. 不能出现0开头的两位以上数字 */
public List<String> restoreIpAddresses(String s) {
List<String> res = new ArrayList<>();
if (s == null || s.length() == 0 || s.length() > 12) {
return res;
}
int n = s.length();
for (int i = 0; i < 3; i++) {
for (int j = i + 1; j < i + 4; j++) {
for (int k = j + 1; k < j + 4; k++) {
if (j < n && k < n) {
String a = s.substring(0, i + 1);
String b = s.substring(i + 1, j + 1);
String c = s.substring(j + 1, k + 1);
String d = s.substring(k + 1);
if (helper(a) && helper(b) && helper(c) && helper(d)) {
StringBuilder sb = new StringBuilder();
sb.append(a)
.append(".")
.append(b)
.append(".")
.append(c)
.append(".")
.append(d);
res.add(sb.toString());
}
}
}
}
}
return res;
}
private boolean helper(String s) {
if (s == null
|| s.length() == 0
|| s.length() > 3
|| s.charAt(0) == '0' && s.length() > 1
|| Integer.parseInt(s) > 255) {
return false;
}
return true;
}
/** 回溯 */
public List<String> restoreIpAddressesII(String s) {
List<String> res = new ArrayList<>();
if (s == null || s.length() == 0 || s.length() > 12) {
return res;
}
int n = s.length();
backtrack(0, "", 4, s, n, res);
return res;
}
/** 回溯本体 */
private void backtrack(int start, String tmp, int flag, String s, int n, List<String> res) {
if (start == n && flag == 0) {
res.add(tmp.substring(0, tmp.length() - 1));
return;
}
if (flag < 0) {
return;
}
for (int j = start; j < start + 3; j++) {
if (j < n) {
if (start == j && s.charAt(j) == '0') {
backtrack(j + 1, tmp + s.charAt(j) + ".", flag - 1, s, n, res);
break;
}
if (Integer.parseInt(s.substring(start, j + 1)) <= 255) {
backtrack(j + 1, tmp + s.substring(start, j + 1) + ".", flag - 1, s, n, res);
}
}
}
}
}
java-leetcode/src/main/java/io/github/wkk/everyday/aug/SameTree.java 0 → 100644
浏览文件 @ aed4a1f3
/* All Contributors (C) 2020 */
package io.github.wkk.everyday.aug;
import io.github.wkk.structs.TreeNode;
/**
* @author kongwiki@163.com
* @since 2020/8/7上午8:58
*/
public class SameTree {
public boolean isSameTree(TreeNode p, TreeNode q) {
if (p == null && q == null) {
return true;
} else if (p == null || q == null) {
return false;
} else if (p.val != q.val) {
return false;
} else {
return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
}
}
}
java-leetcode/src/main/java/io/github/wkk/wkk.md
浏览文件 @ aed4a1f3
......@@ -9,7 +9,9 @@
4. [207. 课程表](./everyday/aug/CourseSchedule.java)
5. [337. 打家劫舍III](./everyday/aug/HouseRobberIII.java)
6. [336. 回文对](./everyday/aug/PalindromePairs.java)
7. [100. 相同的树](./everyday/aug/SameTree.java)
8. [99. 恢复二叉搜索树](./everyday/aug/RecoverBinarySearchTree.java)
9. [93. 复原IP地址](./everyday/aug/RestoreIPAddresses.java)
## 哈希表
1. [1. 两数之和](./TwoSum.java)
rust-leetcode/README.md
浏览文件 @ aed4a1f3
......@@ -20,6 +20,7 @@ Leetcode Rust 实现
* [687 最长同值路径](src/leetcode_687.rs)
* [257 二叉树的所有路径](src/leetcode_257.rs)
* [1443 收集树上所有苹果的最少时间](src/leetcode_1443.rs)
* [515 在每个树行中找最大值](src/leetcode_515.rs)
### unsafe写法
......
rust-leetcode/src/interview_55_1.rs
浏览文件 @ aed4a1f3
......@@ -6,11 +6,13 @@ use crate::pre_structs::{Solution, TreeNode};
///二叉树的深度 = leetcode 104
impl Solution {
//0 ms,100.00%
//2.7 MB,70.37%
pub fn max_depth(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
fn get_depth(root: &Option<Rc<RefCell<TreeNode>>>) -> i32 {
if let Some(root) = root {
let node = root.try_borrow().unwrap();
return max(get_depth(&node.left), get_depth(&node.right)) + 1;
let node = root.borrow();
return max(get_depth(&(node.left)), get_depth(&(node.right))) + 1;
} else {
return 0;
}
......
rust-leetcode/src/leetcode_107.rs
浏览文件 @ aed4a1f3
......@@ -10,6 +10,9 @@ use crate::pre_structs::{Solution, TreeNode};
/// 例如：
/// 给定二叉树 [3,9,20,null,null,15,7],
impl Solution {
//应该用513那种层序
//0 ms,100.00%
//2.2 MB,33.33%
pub fn level_order_bottom(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<Vec<i32>> {
let mut ret = Vec::new();
let mut node_level = VecDeque::new();
......@@ -20,12 +23,12 @@ impl Solution {
let curr_node = node_level.pop_front();
if let Some(node) = curr_node {
if let Some(n) = node {
level.push(n.try_borrow().unwrap().val);
if n.try_borrow().unwrap().left.is_some() {
node_level.push_back(n.try_borrow().unwrap().left.clone());
level.push(n.as_ref().borrow().val);
if n.as_ref().borrow().left.is_some() {
node_level.push_back(n.as_ref().borrow().left.clone());
}
if n.try_borrow().unwrap().right.is_some() {
node_level.push_back(n.try_borrow().unwrap().right.clone());
if n.as_ref().borrow().right.is_some() {
node_level.push_back(n.as_ref().borrow().right.clone());
}
if let Some(f) = flag.borrow() {
if f.as_ptr() == n.as_ptr() {
......
rust-leetcode/src/leetcode_513.rs 0 → 100644
浏览文件 @ aed4a1f3
use std::cell::RefCell;
use std::cmp::max;
use std::collections::VecDeque;
use std::rc::Rc;
use crate::pre_structs::{Solution, TreeNode};
///513. 找树左下角的值
///给定一个二叉树，在树的最后一行找到最左边的值。
impl Solution {
//暴力
//0 ms,100.00%
//3 MB,100.00%
pub fn find_bottom_left_value(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
fn max_depth(root: &Option<Rc<RefCell<TreeNode>>>) -> i32 {
if let Some(root) = root {
let node = root.borrow();
return max(max_depth(&(node.left)), max_depth(&(node.right))) + 1;
} else {
return 0;
}
}
let depth = max_depth(&root);
let mut level = 1;
let mut node_level = VecDeque::new();
node_level.push_back(root.clone());
while !node_level.is_empty() {
let size = node_level.len();
for i in 0..size {
let curr_node = node_level.pop_front();
if let Some(node) = curr_node {
if let Some(n) = node {
if i == 0 && level == depth {
return n.borrow().val;
}
if n.borrow().left.is_some() {
node_level.push_back(n.borrow().left.clone());
}
if n.borrow().right.is_some() {
node_level.push_back(n.borrow().right.clone());
}
}
}
}
level += 1;
}
0
}
//从右开始的层序，最后出队列的元素就是最左的
//0 ms,100.00%
//2.9 MB,100.00%
pub fn find_bottom_left_value2(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
let mut node_level = VecDeque::new();
node_level.push_back(root.clone());
let mut ret: Option<Rc<RefCell<TreeNode>>> = None;
while !node_level.is_empty() {
//题目要求树不能为空，队列元素都是非空
let mut node = node_level.pop_front().unwrap();
ret = node.clone();
if let Some(node) = node {
if node.borrow().right.is_some() {
node_level.push_back(node.borrow().right.clone());
}
if node.borrow().left.is_some() {
node_level.push_back(node.borrow().left.clone());
}
}
}
ret.unwrap().as_ref().borrow().val
}
}
#[cfg(test)]
mod test {
use std::cell::RefCell;
use std::rc::Rc;
use crate::pre_structs::{Solution, TreeNode};
#[test]
fn find_bottom_left_value() {
let e2 = Some(Rc::new(RefCell::new(TreeNode {
val: 2,
left: Some(Rc::new(RefCell::new(TreeNode {
val: 1,
left: None,
right: None,
}))),
right: Some(Rc::new(RefCell::new(TreeNode {
val: 3,
left: None,
right: None,
}))),
})));
let ret = Solution::find_bottom_left_value(e2.clone());
let ret2 = Solution::find_bottom_left_value(e2);
assert!(ret == 1);
assert!(ret2 == 1);
println!("{}", ret);
println!("{}", ret2);
}
}
rust-leetcode/src/leetcode_515.rs 0 → 100644
浏览文件 @ aed4a1f3
use std::cell::RefCell;
use std::cmp::max;
use std::collections::VecDeque;
use std::rc::Rc;
use crate::pre_structs::{Solution, TreeNode};
///515. 在每个树行中找最大值
///您需要在二叉树的每一行中找到最大的值。
impl Solution {
//0 ms,100.00%
//3 MB,100.00%
pub fn largest_values(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<i32> {
if let None = root {
return vec![].to_vec();
}
let mut node_level: VecDeque<Option<Rc<RefCell<TreeNode>>>> = VecDeque::new();
node_level.push_back(root);
let mut ret = Vec::<i32>::new();
let mut max_val = i32::min_value();
while !node_level.is_empty() {
let size = node_level.len();
for i in 0..size {
let curr_node = node_level.pop_front();
if let Some(node) = curr_node {
//应该尽量避免使用unwrap
if let Some(n) = node {
max_val = max(max_val, n.borrow().val);
if n.borrow().left.is_some() {
node_level.push_back(n.borrow().left.clone());
}
if n.borrow().right.is_some() {
node_level.push_back(n.borrow().right.clone());
}
}
}
}
ret.push(max_val);
max_val = i32::min_value();
}
ret
}
}
#[cfg(test)]
mod test {
use std::cell::RefCell;
use std::rc::Rc;
use crate::pre_structs::{print_vec, Solution, TreeNode};
#[test]
fn largest_values() {
let e1 = Some(Rc::new(RefCell::new(TreeNode {
val: 1,
left: Some(Rc::new(RefCell::new(TreeNode {
val: 3,
left: Some(Rc::new(RefCell::new(TreeNode {
val: 5,
left: None,
right: None,
}))),
right: Some(Rc::new(RefCell::new(TreeNode {
val: 3,
left: None,
right: None,
}))),
}))),
right: Some(Rc::new(RefCell::new(TreeNode {
val: 2,
left: None,
right: Some(Rc::new(RefCell::new(TreeNode {
val: 9,
left: None,
right: None,
}))),
}))),
})));
let ret = Solution::largest_values(e1.clone());
print_vec(ret);
}
}
rust-leetcode/src/main.rs
浏览文件 @ aed4a1f3
......@@ -58,6 +58,8 @@ pub mod leetcode_38;
pub mod leetcode_461;
pub mod leetcode_475;
pub mod leetcode_500;
pub mod leetcode_513;
pub mod leetcode_515;
pub mod leetcode_532;
pub mod leetcode_557;
pub mod leetcode_561;
......
scala-leetcode/src/main/scala/io/github/sweeneycai/Leetcode_93.scala 0 → 100644
浏览文件 @ aed4a1f3
/* Licensed under Apache-2.0 (C) All Contributors */
package io.github.sweeneycai
import scala.collection.mutable.ListBuffer
/**
* 93. 复原IP地址 (Medium)
*
* 给定一个只包含数字的字符串，复原它并返回所有可能的 IP 地址格式。
* 有效的 IP 地址正好由四个整数（每个整数位于 0 到 255 之间组成），整数之间用 '.' 分隔。
*/
object Leetcode_93 {
/**
* 简单的深度优先搜索，在 2.13.x 中`Stream`可以使用`LazyList`代替
* 注意考虑'0'作为开头时的特殊情况
*/
def restoreIpAddresses(s: String): List[String] = {
if (s.length > 12 || s.length < 4) List.empty[String]
else {
(for {
i <- from(List(s -> List.empty[String]))
if i._1 == "" && i._2.length == 4
} yield i._2).map(_.mkString(".")).toList
}
}
type Path = (String, List[String])
def generate(s: String): List[(String, String)] = {
val possible = ListBuffer.empty[(String, String)]
if (
s.length >= 3 && (s.charAt(0) == '1' || (s.charAt(0) == '2' && s.substring(0, 3) < "256"))
) {
possible.append(s.splitAt(3))
}
if (s.length >= 2 && s.charAt(0) != '0') possible.append(s.splitAt(2))
if (s.length >= 1) possible.append(s.splitAt(1))
possible.toList
}
def next(s: String, history: List[String]): List[Path] = {
generate(s)
.foldLeft(List.empty[Path]) { (acc, ss) =>
acc :+ (ss._2, history :+ ss._1)
}
.filter(_._2.length <= 4)
}
def from(paths: List[Path]): Stream[Path] =
if (paths.isEmpty)
Stream.empty
else {
val more = for {
path <- paths
next <- next(path._1, path._2)
} yield next
from(more).append(paths)
}
def main(args: Array[String]): Unit = {
println(restoreIpAddresses("25345244"))
}
}
scala-leetcode/src/main/scala/io/github/sweeneycai/Leetcode_99.scala 0 → 100644
浏览文件 @ aed4a1f3
/* Licensed under Apache-2.0 (C) All Contributors */
package io.github.sweeneycai
import io.github.dreamylost.TreeNode
import scala.collection.mutable
/**
* 99. 恢复二叉搜索树 (Hard)
* 二叉搜索树中的两个节点被错误地交换。
*
* 在不改变其结构的情况下，恢复这棵树。
*/
object Leetcode_99 extends App {
/**
* 非递归版本
*/
def recoverTree(root: TreeNode): Unit = {
val stack: mutable.Stack[TreeNode] = mutable.Stack()
var pre = new TreeNode(Int.MinValue)
var bigger: TreeNode = null
var lower: TreeNode = null
var cur = root
while (stack.nonEmpty || cur != null) {
if (cur != null) {
stack.push(cur)
cur = cur.left
} else {
cur = stack.pop()
if (cur.value < pre.value && bigger == null) {
bigger = pre
lower = cur
} else if (cur.value < pre.value) {
lower = cur
}
pre = cur
cur = cur.right
}
}
if (bigger != null && lower != null) {
val value = bigger.value
bigger.value = lower.value
lower.value = value
}
}
/**
* 递归版本
*/
def recoverTreeWithRecur(root: TreeNode): Unit = {
if (root == null) return
var pre = new TreeNode(Int.MinValue)
var bigger: TreeNode = null
var lower: TreeNode = null
def helper(node: TreeNode): Unit = {
if (node.left != null) helper(node.left)
if (node.value < pre.value) {
lower = node
if (bigger == null) bigger = pre
}
pre = node
if (node.right != null) helper(node.right)
}
helper(root)
val value = bigger.value
bigger.value = lower.value
lower.value = value
}
val root = new TreeNode(3)
root.left = new TreeNode(1)
root.right = new TreeNode(4)
root.right.left = new TreeNode(2)
recoverTree(root)
println(root)
}
scala-leetcode/src/main/scala/io/github/sweeneycai/sweeneycai.md
浏览文件 @ aed4a1f3
......@@ -2,9 +2,14 @@
- [707.设计链表](./Leetcode_707.scala)
### 树
- [99.恢复二叉搜索树](./Leetcode_99.scala)
### 深度优先搜索
- [365.水壶问题](./Leetcode_365.scala)
- [93. 复原IP地址](./Leetcode_93.scala)
### 其他
......
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