Add: new

README.md

@@ -54,6 +54,12 @@ LeetCode Problems' Solutions
 
 | # | Title | Solution | Difficulty |
 | :-: | - | - | :-: |
+| <span id="1163">1163</span> | [Last Substring in Lexicographical Order](https://leetcode.com/problems/last-substring-in-lexicographical-order "按字典序排在最后的子串") | [Go](https://github.com/openset/leetcode/tree/master/problems/last-substring-in-lexicographical-order) | Hard |
+| <span id="1162">1162</span> | [As Far from Land as Possible](https://leetcode.com/problems/as-far-from-land-as-possible "地图分析") | [Go](https://github.com/openset/leetcode/tree/master/problems/as-far-from-land-as-possible) | Medium |
+| <span id="1161">1161</span> | [Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree "最大层内元素和") | [Go](https://github.com/openset/leetcode/tree/master/problems/maximum-level-sum-of-a-binary-tree) | Medium |
+| <span id="1160">1160</span> | [Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters "拼写单词") | [Go](https://github.com/openset/leetcode/tree/master/problems/find-words-that-can-be-formed-by-characters) | Easy |
+| <span id="1159">1159</span> | [Market Analysis II](https://leetcode.com/problems/market-analysis-ii) 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/market-analysis-ii) | Hard |
+| <span id="1158">1158</span> | [Market Analysis I](https://leetcode.com/problems/market-analysis-i) 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/market-analysis-i) | Medium |
 | <span id="1157">1157</span> | [Online Majority Element In Subarray](https://leetcode.com/problems/online-majority-element-in-subarray "子数组中占绝大多数的元素") | [Go](https://github.com/openset/leetcode/tree/master/problems/online-majority-element-in-subarray) | Hard |
 | <span id="1156">1156</span> | [Swap For Longest Repeated Character Substring](https://leetcode.com/problems/swap-for-longest-repeated-character-substring "单字符重复子串的最大长度") | [Go](https://github.com/openset/leetcode/tree/master/problems/swap-for-longest-repeated-character-substring) | Medium |
 | <span id="1155">1155</span> | [Number of Dice Rolls With Target Sum](https://leetcode.com/problems/number-of-dice-rolls-with-target-sum "掷骰子的N种方法") | [Go](https://github.com/openset/leetcode/tree/master/problems/number-of-dice-rolls-with-target-sum) | Medium |
@@ -142,7 +148,7 @@ LeetCode Problems' Solutions
 | <span id="1072">1072</span> | [Flip Columns For Maximum Number of Equal Rows](https://leetcode.com/problems/flip-columns-for-maximum-number-of-equal-rows "按列翻转得到最大值等行数") | [Go](https://github.com/openset/leetcode/tree/master/problems/flip-columns-for-maximum-number-of-equal-rows) | Medium |
 | <span id="1071">1071</span> | [Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings "字符串的最大公因子") | [Go](https://github.com/openset/leetcode/tree/master/problems/greatest-common-divisor-of-strings) | Easy |
 | <span id="1070">1070</span> | [Product Sales Analysis III](https://leetcode.com/problems/product-sales-analysis-iii) 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/product-sales-analysis-iii) | Medium |
-| <span id="1069">1069</span> | [Product Sales Analysis II](https://leetcode.com/problems/product-sales-analysis-ii) 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/product-sales-analysis-ii) | Easy |
+| <span id="1069">1069</span> | [Product Sales Analysis II](https://leetcode.com/problems/product-sales-analysis-ii "销售分析Ⅱ") 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/product-sales-analysis-ii) | Easy |
 | <span id="1068">1068</span> | [Product Sales Analysis I](https://leetcode.com/problems/product-sales-analysis-i) 🔒 | [MySQL](https://github.com/openset/leetcode/tree/master/problems/product-sales-analysis-i) | Easy |
 | <span id="1067">1067</span> | [Digit Count in Range](https://leetcode.com/problems/digit-count-in-range "范围内的数字计数") 🔒 | [Go](https://github.com/openset/leetcode/tree/master/problems/digit-count-in-range) | Hard |
 | <span id="1066">1066</span> | [Campus Bikes II](https://leetcode.com/problems/campus-bikes-ii "校园自行车分配 II") 🔒 | [Go](https://github.com/openset/leetcode/tree/master/problems/campus-bikes-ii) | Medium |

problems/as-far-from-land-as-possible/README.md

@@ -0,0 +1,79 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    Openset <[email protected]>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](https://github.com/openset/leetcode/tree/master/problems/maximum-level-sum-of-a-binary-tree "Maximum Level Sum of a Binary Tree")
+
+[Next >](https://github.com/openset/leetcode/tree/master/problems/last-substring-in-lexicographical-order "Last Substring in Lexicographical Order")
+
+## 1162. As Far from Land as Possible (Medium)
+
+<p>Given an N x N <code>grid</code>&nbsp;containing only values <code>0</code> and <code>1</code>, where&nbsp;<code>0</code> represents water&nbsp;and <code>1</code> represents land, find a water cell such that its distance to the nearest land cell is maximized and return the distance.</p>
+
+<p>The distance used in this problem is the <em>Manhattan distance</em>:&nbsp;the distance between two cells <code>(x0, y0)</code> and <code>(x1, y1)</code> is <code>|x0 - x1| + |y0 - y1|</code>.</p>
+
+<p>If no land or water exists in the grid, return <code>-1</code>.</p>
+
+<p>&nbsp;</p>
+
+<p><strong>Example 1:</strong></p>
+
+<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2019/05/03/1336_ex1.JPG" style="width: 185px; height: 87px;" /></strong></p>
+
+<pre>
+<strong>Input: </strong><span id="example-input-1-1">[[1,0,1],[0,0,0],[1,0,1]]</span>
+<strong>Output: </strong><span id="example-output-1">2</span>
+<strong>Explanation: </strong>
+The cell (1, 1) is as far as possible from all the land with distance 2.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2019/05/03/1336_ex2.JPG" style="width: 184px; height: 87px;" /></strong></p>
+
+<pre>
+<strong>Input: </strong><span id="example-input-2-1">[[1,0,0],[0,0,0],[0,0,0]]</span>
+<strong>Output: </strong><span id="example-output-2">4</span>
+<strong>Explanation: </strong>
+The cell (2, 2) is as far as possible from all the land with distance 4.
+</pre>
+
+<p>&nbsp;</p>
+
+<p><span><strong>Note:</strong></span></p>
+
+<ol>
+	<li><span><code>1 &lt;= grid.length == grid[0].length&nbsp;&lt;= 100</code></span></li>
+	<li><span><code>grid[i][j]</code>&nbsp;is <code>0</code> or <code>1</code></span></li>
+</ol>
+
+### Related Topics
+  [[Breadth-first Search](https://github.com/openset/leetcode/tree/master/tag/breadth-first-search/README.md)]
+  [[Graph](https://github.com/openset/leetcode/tree/master/tag/graph/README.md)]
+
+### Similar Questions
+  1. [Shortest Distance from All Buildings](https://github.com/openset/leetcode/tree/master/problems/shortest-distance-from-all-buildings) (Hard)
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Can you think of this problem in a backwards way ?
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Imagine expanding outward from each land cell. What kind of search does that ?
+</details>
+
+<details>
+<summary>Hint 3</summary>
+Use BFS starting from all land cells in the same time.
+</details>
+
+<details>
+<summary>Hint 4</summary>
+When do you reach the furthest water cell?
+</details>

problems/best-time-to-buy-and-sell-stock-iv/README.md

@@ -11,7 +11,7 @@
 
 ## 188. Best Time to Buy and Sell Stock IV (Hard)
 
-<p>Say you have an array for which the <i>i</i><sup>th</sup> element is the price of a given stock on day <i>i</i>.</p>
+<p>Say you have an array for which the <i>i<span style="font-size: 10.8333px;">-</span></i><span style="font-size: 10.8333px;">th</span>&nbsp;element is the price of a given stock on day <i>i</i>.</p>
 
 <p>Design an algorithm to find the maximum profit. You may complete at most <b>k</b> transactions.</p>
 

problems/brace-expansion-ii/README.md

@@ -80,6 +80,9 @@
 ### Related Topics
   [[String](https://github.com/openset/leetcode/tree/master/tag/string/README.md)]
 
+### Similar Questions
+  1. [Brace Expansion](https://github.com/openset/leetcode/tree/master/problems/brace-expansion) (Medium)
+
 ### Hints
 <details>
 <summary>Hint 1</summary>

problems/brace-expansion/README.md

@@ -19,6 +19,7 @@
 ### Similar Questions
   1. [Decode String](https://github.com/openset/leetcode/tree/master/problems/decode-string) (Medium)
   1. [Letter Case Permutation](https://github.com/openset/leetcode/tree/master/problems/letter-case-permutation) (Easy)
+  1. [Brace Expansion II](https://github.com/openset/leetcode/tree/master/problems/brace-expansion-ii) (Hard)
 
 ### Hints
 <details>

problems/convert-sorted-list-to-binary-search-tree/README.md

@@ -30,8 +30,8 @@ One possible answer is: [0,-3,9,-10,null,5], which represents the following heig
 </pre>
 
 ### Related Topics
-  [[Depth-first Search](https://github.com/openset/leetcode/tree/master/tag/depth-first-search/README.md)]
   [[Linked List](https://github.com/openset/leetcode/tree/master/tag/linked-list/README.md)]
+  [[Depth-first Search](https://github.com/openset/leetcode/tree/master/tag/depth-first-search/README.md)]
 
 ### Similar Questions
   1. [Convert Sorted Array to Binary Search Tree](https://github.com/openset/leetcode/tree/master/problems/convert-sorted-array-to-binary-search-tree) (Easy)

problems/day-of-the-year/README.md

@@ -51,3 +51,12 @@
 	<li><code>date[4] == date[7] == &#39;-&#39;</code>, and all other <code>date[i]</code>&#39;s are digits</li>
 	<li><code>date</code> represents a calendar date between Jan 1st, 1900 and Dec 31, 2019.</li>
 </ul>
+
+### Related Topics
+  [[Math](https://github.com/openset/leetcode/tree/master/tag/math/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Have a integer array of how many days there are per month.  February gets one extra day if its a leap year.  Then, we can manually count the ordinal as day + (number of days in months before this one).
+</details>

problems/find-words-that-can-be-formed-by-characters/README.md

@@ -0,0 +1,73 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    Openset <[email protected]>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](https://github.com/openset/leetcode/tree/master/problems/market-analysis-ii "Market Analysis II")
+
+[Next >](https://github.com/openset/leetcode/tree/master/problems/maximum-level-sum-of-a-binary-tree "Maximum Level Sum of a Binary Tree")
+
+## 1160. Find Words That Can Be Formed by Characters (Easy)
+
+<p>You are given an array of strings&nbsp;<code>words</code>&nbsp;and a string&nbsp;<code>chars</code>.</p>
+
+<p>A string is <em>good</em>&nbsp;if&nbsp;it can be formed by&nbsp;characters from <code>chars</code>&nbsp;(each character&nbsp;can only be used once).</p>
+
+<p>Return the sum of lengths of all good strings in <code>words</code>.</p>
+
+<p>&nbsp;</p>
+
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input: </strong>words = <span id="example-input-1-1">[&quot;cat&quot;,&quot;bt&quot;,&quot;hat&quot;,&quot;tree&quot;]</span>, chars = <span id="example-input-1-2">&quot;atach&quot;</span>
+<strong>Output: </strong><span id="example-output-1">6</span>
+<strong>Explanation: </strong>
+The strings that can be formed are &quot;cat&quot; and &quot;hat&quot; so the answer is 3 + 3 = 6.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input: </strong>words = <span id="example-input-2-1">[&quot;hello&quot;,&quot;world&quot;,&quot;leetcode&quot;]</span>, chars = <span id="example-input-2-2">&quot;welldonehoneyr&quot;</span>
+<strong>Output: </strong><span id="example-output-2">10</span>
+<strong>Explanation: </strong>
+The strings that can be formed are &quot;hello&quot; and &quot;world&quot; so the answer is 5 + 5 = 10.
+</pre>
+
+<p>&nbsp;</p>
+
+<p><span><strong>Note:</strong></span></p>
+
+<ol>
+	<li><code>1 &lt;= words.length &lt;= 1000</code></li>
+	<li><code>1 &lt;= words[i].length, chars.length&nbsp;&lt;= 100</code></li>
+	<li>All strings contain lowercase English letters only.</li>
+</ol>
+
+### Related Topics
+  [[Array](https://github.com/openset/leetcode/tree/master/tag/array/README.md)]
+  [[Hash Table](https://github.com/openset/leetcode/tree/master/tag/hash-table/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Solve the problem for each string in <code>words</code> independently.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+Now try to think in frequency of letters.
+</details>
+
+<details>
+<summary>Hint 3</summary>
+Count how many times each character occurs in string <code>chars</code>.
+</details>
+
+<details>
+<summary>Hint 4</summary>
+To form a string using characters from <code>chars</code>, the frequency of each character in <code>chars</code> must be greater than or equal the frequency of that character in the string to be formed.
+</details>

problems/inorder-successor-in-bst/README.md

@@ -11,7 +11,34 @@
 
 ## 285. Inorder Successor in BST (Medium)
 
+<p>Given a binary search tree and a node in it, find the in-order successor of that node in the BST.</p>
 
+<p>The successor of a node&nbsp;<code>p</code>&nbsp;is the node with the smallest key greater than&nbsp;<code>p.val</code>.</p>
+
+<p>&nbsp;</p>
+
+<p><strong>Example 1:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2019/01/23/285_example_1.PNG" style="width: 122px; height: 117px;" />
+<pre><strong>Input: </strong>root = <span id="example-input-1-1">[2,1,3]</span>, p = <span id="example-input-1-2">1</span>
+<strong>Output: </strong><span id="example-output-1">2</span>
+<strong>Explanation: </strong>1&#39;s in-order successor node is 2. Note that both p and the return value is of TreeNode type.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2019/01/23/285_example_2.PNG" style="width: 246px; height: 229px;" />
+<pre><strong>Input: </strong>root = <span id="example-input-2-1">[5,3,6,2,4,null,null,1]</span>, p = <span id="example-input-2-2">6</span>
+<strong>Output: </strong><span id="example-output-2">null</span>
+<strong>Explanation: </strong>There is no in-order successor of the current node, so the answer is <code>null</code>.
+</pre>
+
+<p>&nbsp;</p>
+
+<p><strong>Note:</strong></p>
+
+<ol>
+	<li>If the given node has no in-order successor in the tree, return <code>null</code>.</li>
+	<li>It&#39;s guaranteed that the values of the tree are unique.</li>
+</ol>
 
 ### Related Topics
   [[Tree](https://github.com/openset/leetcode/tree/master/tag/tree/README.md)]

problems/last-substring-in-lexicographical-order/README.md

@@ -0,0 +1,64 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    Openset <[email protected]>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](https://github.com/openset/leetcode/tree/master/problems/as-far-from-land-as-possible "As Far from Land as Possible")
+
+Next >
+
+## 1163. Last Substring in Lexicographical Order (Hard)
+
+<p>Given a string <code>s</code>, return the last substring of <code>s</code> in lexicographical order.</p>
+
+<p>&nbsp;</p>
+
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input: </strong><span id="example-input-1-1">&quot;abab&quot;</span>
+<strong>Output: </strong><span id="example-output-1">&quot;bab&quot;</span>
+<strong>Explanation: </strong>The substrings are [&quot;a&quot;, &quot;ab&quot;, &quot;aba&quot;, &quot;abab&quot;, &quot;b&quot;, &quot;ba&quot;, &quot;bab&quot;]. The lexicographically maximum substring is &quot;bab&quot;.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input: </strong><span id="example-input-2-1">&quot;leetcode&quot;</span>
+<strong>Output: </strong><span id="example-output-2">&quot;tcode&quot;</span>
+</pre>
+
+<p>&nbsp;</p>
+
+<p><strong>Note:</strong></p>
+
+<ol>
+	<li><code>1 &lt;= s.length &lt;= 10^5</code></li>
+	<li><font face="monospace">s</font> contains only lowercase English letters.</li>
+</ol>
+
+### Related Topics
+  [[String](https://github.com/openset/leetcode/tree/master/tag/string/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Assume that the answer is a sub-string from index i to j. If you add the character at index j+1 you get a better answer.
+</details>
+
+<details>
+<summary>Hint 2</summary>
+The answer is always a suffix of the given string.
+</details>
+
+<details>
+<summary>Hint 3</summary>
+Since the limits are high, we need an efficient data structure.
+</details>
+
+<details>
+<summary>Hint 4</summary>
+Use suffix array.
+</details>

problems/market-analysis-i/README.md

@@ -0,0 +1,14 @@
+<!--|This file generated by command(leetcode description); DO NOT EDIT.    |-->
+<!--+----------------------------------------------------------------------+-->
+<!--|@author    Openset <[email protected]>                           |-->
+<!--|@link      https://github.com/openset                                 |-->
+<!--|@home      https://github.com/openset/leetcode                        |-->
+<!--+----------------------------------------------------------------------+-->
+
+[< Previous](https://github.com/openset/leetcode/tree/master/problems/online-majority-element-in-subarray "Online Majority Element In Subarray")
+
+[Next >](https://github.com/openset/leetcode/tree/master/problems/market-analysis-ii "Market Analysis II")
+
+## 1158. Market Analysis I (Medium)
+
+

problems/market-analysis-i/mysql_schemas.sql

@@ -0,0 +1,20 @@
+Create table If Not Exists Users (user_id int, join_date date, favorite_brand varchar(10));
+create table if not exists Orders (order_id int, order_date date, item_id int, buyer_id int, seller_id int);
+create table if not exists Items (item_id int, item_brand varchar(10));
+Truncate table Users;
+insert into Users (user_id, join_date, favorite_brand) values ('1', '2018-01-01', 'Lenovo');
+insert into Users (user_id, join_date, favorite_brand) values ('2', '2018-02-09', 'Samsung');
+insert into Users (user_id, join_date, favorite_brand) values ('3', '2018-01-19', 'LG');
+insert into Users (user_id, join_date, favorite_brand) values ('4', '2018-05-21', 'HP');
+Truncate table Orders;
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('1', '2019-08-01', '4', '1', '2');
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('2', '2018-08-02', '2', '1', '3');
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('3', '2019-08-03', '3', '2', '3');
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('4', '2018-08-04', '1', '4', '2');
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('5', '2018-08-04', '1', '3', '4');
+insert into Orders (order_id, order_date, item_id, buyer_id, seller_id) values ('6', '2019-08-05', '2', '2', '4');
+Truncate table Items;
+insert into Items (item_id, item_brand) values ('1', 'Samsung');
+insert into Items (item_id, item_brand) values ('2', 'Lenovo');
+insert into Items (item_id, item_brand) values ('3', 'LG');
+insert into Items (item_id, item_brand) values ('4', 'HP');