A: new

Author: Shuo

README.md

@@ -70,6 +70,12 @@ LeetCode Problems' Solutions
 
 | # | Title | Solution | Difficulty |
 | :-: | - | - | :-: |
+| <span id="1537">1537</span> | [Get the Maximum Score](https://leetcode.com/problems/get-the-maximum-score "最大得分") | [Go](problems/get-the-maximum-score) | Hard |
+| <span id="1536">1536</span> | [Minimum Swaps to Arrange a Binary Grid](https://leetcode.com/problems/minimum-swaps-to-arrange-a-binary-grid "排布二进制网格的最少交换次数") | [Go](problems/minimum-swaps-to-arrange-a-binary-grid) | Medium |
+| <span id="1535">1535</span> | [Find the Winner of an Array Game](https://leetcode.com/problems/find-the-winner-of-an-array-game "找出数组游戏的赢家") | [Go](problems/find-the-winner-of-an-array-game) | Medium |
+| <span id="1534">1534</span> | [Count Good Triplets](https://leetcode.com/problems/count-good-triplets "统计好三元组") | [Go](problems/count-good-triplets) | Easy |
+| <span id="1533">1533</span> | [Find the Index of the Large Integer](https://leetcode.com/problems/find-the-index-of-the-large-integer) 🔒 | [Go](problems/find-the-index-of-the-large-integer) | Medium |
+| <span id="1532">1532</span> | [The Most Recent Three Orders](https://leetcode.com/problems/the-most-recent-three-orders) 🔒 | [MySQL](problems/the-most-recent-three-orders) | Medium |
 | <span id="1531">1531</span> | [String Compression II](https://leetcode.com/problems/string-compression-ii "压缩字符串 II") | [Go](problems/string-compression-ii) | Hard |
 | <span id="1530">1530</span> | [Number of Good Leaf Nodes Pairs](https://leetcode.com/problems/number-of-good-leaf-nodes-pairs "好叶子节点对的数量") | [Go](problems/number-of-good-leaf-nodes-pairs) | Medium |
 | <span id="1529">1529</span> | [Bulb Switcher IV](https://leetcode.com/problems/bulb-switcher-iv "灯泡开关 IV") | [Go](problems/bulb-switcher-iv) | Medium |
@@ -189,7 +195,7 @@ LeetCode Problems' Solutions
 | <span id="1415">1415</span> | [The k-th Lexicographical String of All Happy Strings of Length n](https://leetcode.com/problems/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n "长度为 n 的开心字符串中字典序第 k 小的字符串") | [Go](problems/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n) | Medium |
 | <span id="1414">1414</span> | [Find the Minimum Number of Fibonacci Numbers Whose Sum Is K](https://leetcode.com/problems/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k "和为 K 的最少斐波那契数字数目") | [Go](problems/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k) | Medium |
 | <span id="1413">1413</span> | [Minimum Value to Get Positive Step by Step Sum](https://leetcode.com/problems/minimum-value-to-get-positive-step-by-step-sum "逐步求和得到正数的最小值") | [Go](problems/minimum-value-to-get-positive-step-by-step-sum) | Easy |
-| <span id="1412">1412</span> | [Find the Quiet Students in All Exams](https://leetcode.com/problems/find-the-quiet-students-in-all-exams "查找成绩处于中游的的学生") 🔒 | [MySQL](problems/find-the-quiet-students-in-all-exams) | Hard |
+| <span id="1412">1412</span> | [Find the Quiet Students in All Exams](https://leetcode.com/problems/find-the-quiet-students-in-all-exams "查找成绩处于中游的学生") 🔒 | [MySQL](problems/find-the-quiet-students-in-all-exams) | Hard |
 | <span id="1411">1411</span> | [Number of Ways to Paint N × 3 Grid](https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid "给 N x 3 网格图涂色的方案数") | [Go](problems/number-of-ways-to-paint-n-3-grid) | Hard |
 | <span id="1410">1410</span> | [HTML Entity Parser](https://leetcode.com/problems/html-entity-parser "HTML 实体解析器") | [Go](problems/html-entity-parser) | Medium |
 | <span id="1409">1409</span> | [Queries on a Permutation With Key](https://leetcode.com/problems/queries-on-a-permutation-with-key "查询带键的排列") | [Go](problems/queries-on-a-permutation-with-key) | Medium |

problems/all-paths-from-source-to-target/README.md

@@ -11,14 +11,14 @@
 
 ## [797. All Paths From Source to Target (Medium)](https://leetcode.com/problems/all-paths-from-source-to-target "所有可能的路径")
 
-<p>Given a directed, acyclic graph of <code>N</code> nodes.&nbsp; Find all possible paths from node <code>0</code> to node <code>N-1</code>, and return them in any order.</p>
+<p>Given a directed&nbsp;acyclic graph of <code>N</code> nodes.&nbsp;Find all possible paths from node <code>0</code> to node <code>N-1</code>, and return them in any order.</p>
 
 <p>The graph is given as follows:&nbsp; the nodes are 0, 1, ..., graph.length - 1.&nbsp; graph[i] is a list of all nodes j for which the edge (i, j) exists.</p>
 
 <pre>
 <strong>Example:</strong>
-<strong>Input:</strong> [[1,2], [3], [3], []] 
-<strong>Output:</strong> [[0,1,3],[0,2,3]] 
+<strong>Input:</strong> [[1,2],[3],[3],[]]
+<strong>Output:</strong> [[0,1,3],[0,2,3]]
 <strong>Explanation:</strong> The graph looks like this:
 0---&gt;1
 |    |
@@ -27,7 +27,8 @@ v    v
 There are two paths: 0 -&gt; 1 -&gt; 3 and 0 -&gt; 2 -&gt; 3.
 </pre>
 
-<p><strong>Note:</strong></p>
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
 
 <ul>
 	<li>The number of nodes in the graph will be in the range <code>[2, 15]</code>.</li>

problems/brace-expansion/README.md

@@ -50,7 +50,7 @@
 
 ### Similar Questions
   1. [Decode String](../decode-string) (Medium)
-  1. [Letter Case Permutation](../letter-case-permutation) (Easy)
+  1. [Letter Case Permutation](../letter-case-permutation) (Medium)
   1. [Brace Expansion II](../brace-expansion-ii) (Hard)
 
 ### Hints

problems/count-good-triplets/README.md

@@ -0,0 +1,67 @@
+<!--|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](../find-the-index-of-the-large-integer "Find the Index of the Large Integer")
+　　　　　　　　　　　　　　　　
+[Next >](../find-the-winner-of-an-array-game "Find the Winner of an Array Game")
+
+## [1534. Count Good Triplets (Easy)](https://leetcode.com/problems/count-good-triplets "统计好三元组")
+
+<p>Given an array of integers <code>arr</code>, and three integers&nbsp;<code>a</code>,&nbsp;<code>b</code>&nbsp;and&nbsp;<code>c</code>. You need to find the number of good triplets.</p>
+
+<p>A triplet <code>(arr[i], arr[j], arr[k])</code>&nbsp;is <strong>good</strong> if the following conditions are true:</p>
+
+<ul>
+	<li><code>0 &lt;= i &lt; j &lt; k &lt;&nbsp;arr.length</code></li>
+	<li><code>|arr[i] - arr[j]| &lt;= a</code></li>
+	<li><code>|arr[j] - arr[k]| &lt;= b</code></li>
+	<li><code>|arr[i] - arr[k]| &lt;= c</code></li>
+</ul>
+
+<p>Where <code>|x|</code> denotes the absolute value of <code>x</code>.</p>
+
+<p>Return<em> the number of good triplets</em>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [3,0,1,1,9,7], a = 7, b = 2, c = 3
+<strong>Output:</strong> 4
+<strong>Explanation:</strong>&nbsp;There are 4 good triplets: [(3,0,1), (3,0,1), (3,1,1), (0,1,1)].
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [1,1,2,2,3], a = 0, b = 0, c = 1
+<strong>Output:</strong> 0
+<strong>Explanation: </strong>No triplet satisfies all conditions.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>3 &lt;= arr.length &lt;= 100</code></li>
+	<li><code>0 &lt;= arr[i] &lt;= 1000</code></li>
+	<li><code>0 &lt;= a, b, c &lt;= 1000</code></li>
+</ul>
+
+### Related Topics
+  [[Array](../../tag/array/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Notice that the constraints are small enough for a brute force solution to pass.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Loop through all triplets, and count the ones that are good.
+</details>

problems/find-the-index-of-the-large-integer/README.md

@@ -0,0 +1,28 @@
+<!--|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-most-recent-three-orders "The Most Recent Three Orders")
+　　　　　　　　　　　　　　　　
+[Next >](../count-good-triplets "Count Good Triplets")
+
+## [1533. Find the Index of the Large Integer (Medium)](https://leetcode.com/problems/find-the-index-of-the-large-integer "")
+
+
+
+### Related Topics
+  [[Binary Search](../../tag/binary-search/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Do a binary search over the array, exclude the half of the array that doesn't contain the largest number.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Keep shrinking the search space till it reaches the size of 2 where you can easily determine which one has the largest integer.
+</details>

problems/find-the-quiet-students-in-all-exams/README.md

@@ -9,6 +9,6 @@
 
 [Next >](../minimum-value-to-get-positive-step-by-step-sum "Minimum Value to Get Positive Step by Step Sum")
 
-## [1412. Find the Quiet Students in All Exams (Hard)](https://leetcode.com/problems/find-the-quiet-students-in-all-exams "查找成绩处于中游的的学生")
+## [1412. Find the Quiet Students in All Exams (Hard)](https://leetcode.com/problems/find-the-quiet-students-in-all-exams "查找成绩处于中游的学生")
 
 

problems/find-the-winner-of-an-array-game/README.md

@@ -0,0 +1,81 @@
+<!--|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](../count-good-triplets "Count Good Triplets")
+　　　　　　　　　　　　　　　　
+[Next >](../minimum-swaps-to-arrange-a-binary-grid "Minimum Swaps to Arrange a Binary Grid")
+
+## [1535. Find the Winner of an Array Game (Medium)](https://leetcode.com/problems/find-the-winner-of-an-array-game "找出数组游戏的赢家")
+
+<p>Given an integer array <code>arr</code> of <strong>distinct</strong> integers and an integer <code>k</code>.</p>
+
+<p>A game will be played between the first two elements of the array (i.e. <code>arr[0]</code> and <code>arr[1]</code>). In each round of the game, we compare <code>arr[0]</code> with <code>arr[1]</code>, the larger integer&nbsp;wins and remains at position <code>0</code> and the smaller integer moves to the end of the array. The game ends when an integer wins <code>k</code> consecutive rounds.</p>
+
+<p>Return <em>the integer which will win the game</em>.</p>
+
+<p>It is <strong>guaranteed</strong> that there will be a winner of the game.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [2,1,3,5,4,6,7], k = 2
+<strong>Output:</strong> 5
+<strong>Explanation:</strong> Let&#39;s see the rounds of the game:
+Round |       arr       | winner | win_count
+  1   | [2,1,3,5,4,6,7] | 2      | 1
+  2   | [2,3,5,4,6,7,1] | 3      | 1
+  3   | [3,5,4,6,7,1,2] | 5      | 1
+  4   | [5,4,6,7,1,2,3] | 5      | 2
+So we can see that 4 rounds will be played and 5 is the winner because it wins 2 consecutive games.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [3,2,1], k = 10
+<strong>Output:</strong> 3
+<strong>Explanation:</strong> 3 will win the first 10 rounds consecutively.
+</pre>
+
+<p><strong>Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [1,9,8,2,3,7,6,4,5], k = 7
+<strong>Output:</strong> 9
+</pre>
+
+<p><strong>Example 4:</strong></p>
+
+<pre>
+<strong>Input:</strong> arr = [1,11,22,33,44,55,66,77,88,99], k = 1000000000
+<strong>Output:</strong> 99
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>2 &lt;= arr.length &lt;= 10^5</code></li>
+	<li><code>1 &lt;= arr[i] &lt;= 10^6</code></li>
+	<li><code>arr</code> contains <b>distinct</b>&nbsp;integers.</li>
+	<li><code>1 &lt;= k &lt;= 10^9</code></li>
+</ul>
+
+### Related Topics
+  [[Array](../../tag/array/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+If k ≥ arr.length return the max element of the array.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+If k < arr.length simulate the game until a number wins k consecutive games.
+</details>

problems/first-missing-positive/README.md

@@ -34,7 +34,7 @@ Input: [7,8,9,11,12]
 Output: 1
 </pre>
 
-<p><strong>Note:</strong></p>
+<p><strong>Follow up:</strong></p>
 
 <p>Your algorithm should run in <em>O</em>(<em>n</em>) time and uses constant extra space.</p>
 

problems/fraction-to-recurring-decimal/README.md

@@ -15,6 +15,8 @@
 
 <p>If the fractional part is repeating, enclose the repeating part in parentheses.</p>
 
+<p>If multiple answers are possible, just return any of them.</p>
+
 <p><strong>Example 1:</strong></p>
 
 <pre>

problems/get-the-maximum-score/README.md

@@ -0,0 +1,85 @@
+<!--|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](../minimum-swaps-to-arrange-a-binary-grid "Minimum Swaps to Arrange a Binary Grid")
+　　　　　　　　　　　　　　　　
+Next >
+
+## [1537. Get the Maximum Score (Hard)](https://leetcode.com/problems/get-the-maximum-score "最大得分")
+
+<p>You are given two <strong>sorted</strong> arrays of distinct integers <code>nums1</code> and <code>nums2.</code></p>
+
+<p>A <strong>valid<strong><em> </em></strong>path</strong> is defined as follows:</p>
+
+<ul>
+	<li>Choose&nbsp;array nums1 or nums2 to traverse (from index-0).</li>
+	<li>Traverse the current array from left to right.</li>
+	<li>If you are reading any value that is present in <code>nums1</code> and <code>nums2</code>&nbsp;you are allowed to change your path to the other array. (Only one repeated value is considered in the&nbsp;valid path).</li>
+</ul>
+
+<p><em>Score</em> is defined as the sum of uniques values in a valid path.</p>
+
+<p>Return the maximum <em>score</em> you can obtain of all possible&nbsp;<strong>valid&nbsp;paths</strong>.</p>
+
+<p>Since the answer&nbsp;may be too large,&nbsp;return it modulo&nbsp;10^9 + 7.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2020/07/16/sample_1_1893.png" style="width: 538px; height: 163px;" /></strong></p>
+
+<pre>
+<strong>Input:</strong> nums1 = [2,4,5,8,10], nums2 = [4,6,8,9]
+<strong>Output:</strong> 30
+<strong>Explanation:</strong>&nbsp;Valid paths:
+[2,4,5,8,10], [2,4,5,8,9], [2,4,6,8,9], [2,4,6,8,10],  (starting from nums1)
+[4,6,8,9], [4,5,8,10], [4,5,8,9], [4,6,8,10]    (starting from nums2)
+The maximum is obtained with the path in green <strong>[2,4,6,8,10]</strong>.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums1 = [1,3,5,7,9], nums2 = [3,5,100]
+<strong>Output:</strong> 109
+<strong>Explanation:</strong>&nbsp;Maximum sum is obtained with the path <strong>[1,3,5,100]</strong>.
+</pre>
+
+<p><strong>Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums1 = [1,2,3,4,5], nums2 = [6,7,8,9,10]
+<strong>Output:</strong> 40
+<strong>Explanation:</strong>&nbsp;There are no common elements between nums1 and nums2.
+Maximum sum is obtained with the path [6,7,8,9,10].
+</pre>
+
+<p><strong>Example 4:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums1 = [1,4,5,8,9,11,19], nums2 = [2,3,4,11,12]
+<strong>Output:</strong> 61
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums1.length &lt;= 10^5</code></li>
+	<li><code>1 &lt;= nums2.length &lt;= 10^5</code></li>
+	<li><code>1 &lt;= nums1[i], nums2[i] &lt;= 10^7</code></li>
+	<li><code>nums1</code> and <code>nums2</code> are strictly increasing.</li>
+</ul>
+
+### Related Topics
+  [[Dynamic Programming](../../tag/dynamic-programming/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Partition the array by common integers, and choose the path with larger sum with a DP technique.
+</details>