A: new

Author: Shuo

README.md

@@ -62,20 +62,26 @@ LeetCode Problems' Solutions
 
 | # | Title | Solution | Difficulty |
 | :-: | - | - | :-: |
-| <span id="1467">1467</span> | [Probability of a Two Boxes Having The Same Number of Distinct Balls](https://leetcode.com/problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls "两个盒子中不同颜色的球数量相同的概率") | [Go](problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls) | Hard |
+| <span id="1473">1473</span> | [Paint House III](https://leetcode.com/problems/paint-house-iii "给房子涂色 III") | [Go](problems/paint-house-iii) | Hard |
+| <span id="1472">1472</span> | [Design Browser History](https://leetcode.com/problems/design-browser-history "设计浏览器历史记录") | [Go](problems/design-browser-history) | Medium |
+| <span id="1471">1471</span> | [The k Strongest Values in an Array](https://leetcode.com/problems/the-k-strongest-values-in-an-array "数组中的 k 个最强值") | [Go](problems/the-k-strongest-values-in-an-array) | Medium |
+| <span id="1470">1470</span> | [Shuffle the Array](https://leetcode.com/problems/shuffle-the-array "重新排列数组") | [Go](problems/shuffle-the-array) | Easy |
+| <span id="1469">1469</span> | [Find All The Lonely Nodes](https://leetcode.com/problems/find-all-the-lonely-nodes) 🔒 | [Go](problems/find-all-the-lonely-nodes) | Easy |
+| <span id="1468">1468</span> | [Calculate Salaries](https://leetcode.com/problems/calculate-salaries) 🔒 | [MySQL](problems/calculate-salaries) | Medium |
+| <span id="1467">1467</span> | [Probability of a Two Boxes Having The Same Number of Distinct Balls](https://leetcode.com/problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls "两个盒子中球的颜色数相同的概率") | [Go](problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls) | Hard |
 | <span id="1466">1466</span> | [Reorder Routes to Make All Paths Lead to the City Zero](https://leetcode.com/problems/reorder-routes-to-make-all-paths-lead-to-the-city-zero "重新规划路线") | [Go](problems/reorder-routes-to-make-all-paths-lead-to-the-city-zero) | Medium |
 | <span id="1465">1465</span> | [Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts](https://leetcode.com/problems/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts "切割后面积最大的蛋糕") | [Go](problems/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts) | Medium |
 | <span id="1464">1464</span> | [Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array "数组中两元素的最大乘积") | [Go](problems/maximum-product-of-two-elements-in-an-array) | Easy |
 | <span id="1463">1463</span> | [Cherry Pickup II](https://leetcode.com/problems/cherry-pickup-ii "摘樱桃 II") | [Go](problems/cherry-pickup-ii) | Hard |
 | <span id="1462">1462</span> | [Course Schedule IV](https://leetcode.com/problems/course-schedule-iv "课程安排 IV") | [Go](problems/course-schedule-iv) | Medium |
-| <span id="1461">1461</span> | [Check If a String Contains All Binary Codes of Size K](https://leetcode.com/problems/check-if-a-string-contains-all-binary-codes-of-size-k "检查一个字符串是否包含所有大小为 K 的二进制子串") | [Go](problems/check-if-a-string-contains-all-binary-codes-of-size-k) | Medium |
+| <span id="1461">1461</span> | [Check If a String Contains All Binary Codes of Size K](https://leetcode.com/problems/check-if-a-string-contains-all-binary-codes-of-size-k "检查一个字符串是否包含所有长度为 K 的二进制子串") | [Go](problems/check-if-a-string-contains-all-binary-codes-of-size-k) | Medium |
 | <span id="1460">1460</span> | [Make Two Arrays Equal by Reversing Sub-arrays](https://leetcode.com/problems/make-two-arrays-equal-by-reversing-sub-arrays "通过翻转子数组使两个数组相等") | [Go](problems/make-two-arrays-equal-by-reversing-sub-arrays) | Easy |
-| <span id="1459">1459</span> | [Rectangles Area](https://leetcode.com/problems/rectangles-area) 🔒 | [MySQL](problems/rectangles-area) | Medium |
+| <span id="1459">1459</span> | [Rectangles Area](https://leetcode.com/problems/rectangles-area "矩形面积") 🔒 | [MySQL](problems/rectangles-area) | Medium |
 | <span id="1458">1458</span> | [Max Dot Product of Two Subsequences](https://leetcode.com/problems/max-dot-product-of-two-subsequences "两个子序列的最大点积") | [Go](problems/max-dot-product-of-two-subsequences) | Hard |
 | <span id="1457">1457</span> | [Pseudo-Palindromic Paths in a Binary Tree](https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree "二叉树中的伪回文路径") | [Go](problems/pseudo-palindromic-paths-in-a-binary-tree) | Medium |
 | <span id="1456">1456</span> | [Maximum Number of Vowels in a Substring of Given Length](https://leetcode.com/problems/maximum-number-of-vowels-in-a-substring-of-given-length "定长子串中元音的最大数目") | [Go](problems/maximum-number-of-vowels-in-a-substring-of-given-length) | Medium |
 | <span id="1455">1455</span> | [Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence "检查单词是否为句中其他单词的前缀") | [Go](problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence) | Easy |
-| <span id="1454">1454</span> | [Active Users](https://leetcode.com/problems/active-users) 🔒 | [MySQL](problems/active-users) | Medium |
+| <span id="1454">1454</span> | [Active Users](https://leetcode.com/problems/active-users " 活跃用户") 🔒 | [MySQL](problems/active-users) | Medium |
 | <span id="1453">1453</span> | [Maximum Number of Darts Inside of a Circular Dartboard](https://leetcode.com/problems/maximum-number-of-darts-inside-of-a-circular-dartboard "圆形靶内的最大飞镖数量") | [Go](problems/maximum-number-of-darts-inside-of-a-circular-dartboard) | Hard |
 | <span id="1452">1452</span> | [People Whose List of Favorite Companies Is Not a Subset of Another List](https://leetcode.com/problems/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list "收藏清单") | [Go](problems/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list) | Medium |
 | <span id="1451">1451</span> | [Rearrange Words in a Sentence](https://leetcode.com/problems/rearrange-words-in-a-sentence "重新排列句子中的单词") | [Go](problems/rearrange-words-in-a-sentence) | Medium |

problems/active-users/README.md

@@ -9,6 +9,6 @@
 
 [Next >](../check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence "Check If a Word Occurs As a Prefix of Any Word in a Sentence")
 
-## [1454. Active Users (Medium)](https://leetcode.com/problems/active-users "")
+## [1454. Active Users (Medium)](https://leetcode.com/problems/active-users " 活跃用户")
 
 

problems/calculate-salaries/README.md

@@ -0,0 +1,14 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    openset <openset.wang@gmail.com>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](../probability-of-a-two-boxes-having-the-same-number-of-distinct-balls "Probability of a Two Boxes Having The Same Number of Distinct Balls")
+　　　　　　　　　　　　　　　　
+[Next >](../find-all-the-lonely-nodes "Find All The Lonely Nodes")
+
+## [1468. Calculate Salaries (Medium)](https://leetcode.com/problems/calculate-salaries "")
+
+

problems/calculate-salaries/mysql_schemas.sql

@@ -0,0 +1,12 @@
+Create table If Not Exists Salaries (company_id int, employee_id int, employee_name varchar(13), salary int);
+Truncate table Salaries;
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('1', '1', 'Tony', '2000');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('1', '2', 'Pronub', '21300');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('1', '3', 'Tyrrox', '10800');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('2', '1', 'Pam', '300');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('2', '7', 'Bassem', '450');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('2', '9', 'Hermione', '700');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('3', '7', 'Bocaben', '100');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('3', '2', 'Ognjen', '2200');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('3', '13', 'Nyancat', '3300');
+insert into Salaries (company_id, employee_id, employee_name, salary) values ('3', '15', 'Morninngcat', '7777');

problems/cheapest-flights-within-k-stops/README.md

@@ -11,7 +11,7 @@
 
 ## [787. Cheapest Flights Within K Stops (Medium)](https://leetcode.com/problems/cheapest-flights-within-k-stops "K 站中转内最便宜的航班")
 
-<p>There are <code>n</code> cities connected by&nbsp;<code>m</code> flights. Each flight starts from city&nbsp;<code>u </code>and arrives at&nbsp;<code>v</code> with a price <code>w</code>.</p>
+<p>There are <code>n</code> cities connected by&nbsp;<code>m</code> flights. Each flight starts from city&nbsp;<code>u</code> and arrives at&nbsp;<code>v</code> with a price <code>w</code>.</p>
 
 <p>Now given all the cities and flights, together with starting city <code>src</code> and the destination&nbsp;<code>dst</code>, your task is to find the cheapest price from <code>src</code> to <code>dst</code> with up to <code>k</code> stops. If there is no such route, output <code>-1</code>.</p>
 
@@ -37,9 +37,11 @@ src = 0, dst = 2, k = 0
 The graph looks like this:
 <img alt="" src="https://s3-lc-upload.s3.amazonaws.com/uploads/2018/02/16/995.png" style="height:180px; width:246px" />
 
-The cheapest price from city <code>0</code> to city <code>2</code> with at most 0 stop costs 500, as marked blue in the picture.</pre>
+The cheapest price from city <code>0</code> to city <code>2</code> with at most 0 stop costs 500, as marked blue in the picture.
+</pre>
 
-<p><strong>Note:</strong></p>
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
 
 <ul>
 	<li>The number of&nbsp;nodes&nbsp;<code>n</code> will be&nbsp;in range <code>[1, 100]</code>, with nodes labeled from <code>0</code> to <code>n</code><code> - 1</code>.</li>

problems/continuous-subarray-sum/README.md

@@ -32,13 +32,12 @@
 </pre>
 
 <p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
 
-<p><b>Note:</b></p>
-
-<ol>
+<ul>
 	<li>The length of the array won&#39;t exceed 10,000.</li>
 	<li>You may assume the sum of all the numbers is in the range of a signed 32-bit integer.</li>
-</ol>
+</ul>
 
 ### Related Topics
   [[Math](../../tag/math/README.md)]

problems/decode-string/README.md

@@ -19,15 +19,20 @@
 
 <p>Furthermore, you may assume that the original data does not contain any digits and that digits are only for those repeat numbers, <i>k</i>. For example, there won&#39;t be input like <code>3a</code> or <code>2[4]</code>.</p>
 
-<p><b>Examples:</b></p>
-
-<pre>
-s = &quot;3[a]2[bc]&quot;, return &quot;aaabcbc&quot;.
-s = &quot;3[a2[c]]&quot;, return &quot;accaccacc&quot;.
-s = &quot;2[abc]3[cd]ef&quot;, return &quot;abcabccdcdcdef&quot;.
-</pre>
-
 <p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+<pre><strong>Input:</strong> s = "3[a]2[bc]"
+<strong>Output:</strong> "aaabcbc"
+</pre><p><strong>Example 2:</strong></p>
+<pre><strong>Input:</strong> s = "3[a2[c]]"
+<strong>Output:</strong> "accaccacc"
+</pre><p><strong>Example 3:</strong></p>
+<pre><strong>Input:</strong> s = "2[abc]3[cd]ef"
+<strong>Output:</strong> "abcabccdcdcdef"
+</pre><p><strong>Example 4:</strong></p>
+<pre><strong>Input:</strong> s = "abc3[cd]xyz"
+<strong>Output:</strong> "abccdcdcdxyz"
+</pre>
 
 ### Related Topics
   [[Stack](../../tag/stack/README.md)]

problems/delete-leaves-with-a-given-value/README.md

@@ -65,7 +65,7 @@ After removing, new nodes become leaf nodes with value (target = 2) (Picture in
 
 <ul>
 	<li><code>1 &lt;= target&nbsp;&lt;= 1000</code></li>
-	<li>Each tree has at most <code>3000</code> nodes.</li>
+	<li>The&nbsp;given binary tree will have between&nbsp;<code>1</code>&nbsp;and&nbsp;<code>3000</code>&nbsp;nodes.</li>
 	<li>Each node&#39;s value is between <code>[1, 1000]</code>.</li>
 </ul>
 

problems/design-browser-history/README.md

@@ -0,0 +1,72 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    openset <openset.wang@gmail.com>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](../the-k-strongest-values-in-an-array "The k Strongest Values in an Array")
+　　　　　　　　　　　　　　　　
+[Next >](../paint-house-iii "Paint House III")
+
+## [1472. Design Browser History (Medium)](https://leetcode.com/problems/design-browser-history "设计浏览器历史记录")
+
+<p>You have a <strong>browser</strong> of one tab where you start on the <code>homepage</code> and you can visit another <code>url</code>, get back in the history number of <code>steps</code> or move forward in the history number of <code>steps</code>.</p>
+
+<p>Implement the <code>BrowserHistory</code> class:</p>
+
+<ul>
+	<li><code>BrowserHistory(string homepage)</code> Initializes the object with the <code>homepage</code>&nbsp;of the browser.</li>
+	<li><code>void visit(string url)</code>&nbsp;visits <code>url</code> from the current page. It clears up all the forward history.</li>
+	<li><code>string back(int steps)</code>&nbsp;Move <code>steps</code> back in history. If you can only return <code>x</code> steps in the history and <code>steps &gt; x</code>, you will&nbsp;return only <code>x</code> steps. Return the current <code>url</code>&nbsp;after moving back in history <strong>at most</strong> <code>steps</code>.</li>
+	<li><code>string forward(int steps)</code>&nbsp;Move <code>steps</code> forward in history. If you can only forward <code>x</code> steps in the history and <code>steps &gt; x</code>, you will&nbsp;forward only&nbsp;<code>x</code> steps. Return the current <code>url</code>&nbsp;after forwarding in history <strong>at most</strong> <code>steps</code>.</li>
+</ul>
+
+<p>&nbsp;</p>
+<p><strong>Example:</strong></p>
+
+<pre>
+<b>Input:</b>
+[&quot;BrowserHistory&quot;,&quot;visit&quot;,&quot;visit&quot;,&quot;visit&quot;,&quot;back&quot;,&quot;back&quot;,&quot;forward&quot;,&quot;visit&quot;,&quot;forward&quot;,&quot;back&quot;,&quot;back&quot;]
+[[&quot;leetcode.com&quot;],[&quot;google.com&quot;],[&quot;facebook.com&quot;],[&quot;youtube.com&quot;],[1],[1],[1],[&quot;linkedin.com&quot;],[2],[2],[7]]
+<b>Output:</b>
+[null,null,null,null,&quot;facebook.com&quot;,&quot;google.com&quot;,&quot;facebook.com&quot;,null,&quot;linkedin.com&quot;,&quot;google.com&quot;,&quot;leetcode.com&quot;]
+
+<b>Explanation:</b>
+BrowserHistory browserHistory = new BrowserHistory(&quot;leetcode.com&quot;);
+browserHistory.visit(&quot;google.com&quot;);       // You are in &quot;leetcode.com&quot;. Visit &quot;google.com&quot;
+browserHistory.visit(&quot;facebook.com&quot;);     // You are in &quot;google.com&quot;. Visit &quot;facebook.com&quot;
+browserHistory.visit(&quot;youtube.com&quot;);      // You are in &quot;facebook.com&quot;. Visit &quot;youtube.com&quot;
+browserHistory.back(1);                   // You are in &quot;youtube.com&quot;, move back to &quot;facebook.com&quot; return &quot;facebook.com&quot;
+browserHistory.back(1);                   // You are in &quot;facebook.com&quot;, move back to &quot;google.com&quot; return &quot;google.com&quot;
+browserHistory.forward(1);                // You are in &quot;google.com&quot;, move forward to &quot;facebook.com&quot; return &quot;facebook.com&quot;
+browserHistory.visit(&quot;linkedin.com&quot;);     // You are in &quot;facebook.com&quot;. Visit &quot;linkedin.com&quot;
+browserHistory.forward(2);                // You are in &quot;linkedin.com&quot;, you cannot move forward any steps.
+browserHistory.back(2);                   // You are in &quot;linkedin.com&quot;, move back two steps to &quot;facebook.com&quot; then to &quot;google.com&quot;. return &quot;google.com&quot;
+browserHistory.back(7);                   // You are in &quot;google.com&quot;, you can move back only one step to &quot;leetcode.com&quot;. return &quot;leetcode.com&quot;
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= homepage.length &lt;= 20</code></li>
+	<li><code>1 &lt;= url.length &lt;= 20</code></li>
+	<li><code>1 &lt;= steps &lt;= 100</code></li>
+	<li><code>homepage</code> and <code>url</code> consist of&nbsp; &#39;.&#39; or lower case English letters.</li>
+	<li>At most <code>5000</code>&nbsp;calls will be made to <code>visit</code>, <code>back</code>, and <code>forward</code>.</li>
+</ul>
+
+### Related Topics
+  [[Design](../../tag/design/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Use two stack one for back history and one for forward history and simulate the functions.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Can you do faster by using different data structure ?
+</details>

problems/find-all-the-lonely-nodes/README.md

@@ -0,0 +1,29 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    openset <openset.wang@gmail.com>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](../calculate-salaries "Calculate Salaries")
+　　　　　　　　　　　　　　　　
+[Next >](../shuffle-the-array "Shuffle the Array")
+
+## [1469. Find All The Lonely Nodes (Easy)](https://leetcode.com/problems/find-all-the-lonely-nodes "")
+
+
+
+### Related Topics
+  [[Tree](../../tag/tree/README.md)]
+  [[Depth-first Search](../../tag/depth-first-search/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Do a simple tree traversal, try to check if the current node is lonely or not.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Node is lonely if at least one of the left/right pointers is null.
+</details>