feat: add biweekly contest 171 (#4882)

Author: yanglbme

solution/0900-0999/0955.Delete Columns to Make Sorted II/README_EN.md

@@ -32,7 +32,7 @@ tags:
 <pre>
 <strong>Input:</strong> strs = [&quot;ca&quot;,&quot;bb&quot;,&quot;ac&quot;]
 <strong>Output:</strong> 1
-<strong>Explanation:</strong>
+<strong>Explanation:</strong> 
 After deleting the first column, strs = [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;].
 Now strs is in lexicographic order (ie. strs[0] &lt;= strs[1] &lt;= strs[2]).
 We require at least 1 deletion since initially strs was not in lexicographic order, so the answer is 1.
@@ -43,7 +43,7 @@ We require at least 1 deletion since initially strs was not in lexicographic ord
 <pre>
 <strong>Input:</strong> strs = [&quot;xc&quot;,&quot;yb&quot;,&quot;za&quot;]
 <strong>Output:</strong> 0
-<strong>Explanation:</strong>
+<strong>Explanation:</strong> 
 strs is already in lexicographic order, so we do not need to delete anything.
 Note that the rows of strs are not necessarily in lexicographic order:
 i.e., it is NOT necessarily true that (strs[0][0] &lt;= strs[0][1] &lt;= ...)

solution/1500-1599/1523.Count Odd Numbers in an Interval Range/README.md

@@ -50,7 +50,9 @@ tags:
 
 ### 方法一：前缀和思想
 
-`[0, x]` 之间的奇数个数为 `(x + 1) >> 1`，那么 `[low, high]` 之间的奇数个数为 `((high + 1) >> 1) - (low >> 1)`。
+我们知道，在 $[0, x]$ 范围内奇数的个数为 $\lfloor\frac{x+1}{2}\rfloor$。因此，$[low, high]$ 范围内奇数的个数为 $\lfloor\frac{high+1}{2}\rfloor - \lfloor\frac{low}{2}\rfloor$。
+
+时间复杂度 $O(1)$，空间复杂度 $O(1)$。
 
 <!-- tabs:start -->
 

solution/1500-1599/1523.Count Odd Numbers in an Interval Range/README_EN.md

@@ -58,7 +58,11 @@ tags:
 
 <!-- solution:start -->
 
-### Solution 1
+### Solution 1: Prefix Sum Concept
+
+We know that the count of odd numbers in the range $[0, x]$ is $\lfloor\frac{x+1}{2}\rfloor$. Therefore, the count of odd numbers in the range $[low, high]$ is $\lfloor\frac{high+1}{2}\rfloor - \lfloor\frac{low}{2}\rfloor$.
+
+The time complexity is $O(1)$, and the space complexity is $O(1)$.
 
 <!-- tabs:start -->
 

solution/3700-3799/3764.Most Common Course Pairs/README.md

@@ -20,7 +20,7 @@ tags:
 
 <pre>
 +-------------------+---------+
-| Column Name       | Type    |
+| Column Name       | Type    | 
 +-------------------+---------+
 | user_id           | int     |
 | course_id         | int     |

solution/3700-3799/3764.Most Common Course Pairs/README_EN.md

@@ -20,7 +20,7 @@ tags:
 
 <pre>
 +-------------------+---------+
-| Column Name       | Type    |
+| Column Name       | Type    | 
 +-------------------+---------+
 | user_id           | int     |
 | course_id         | int     |

solution/3700-3799/3765.Complete Prime Number/README.md

@@ -0,0 +1,126 @@
+---
+comments: true
+difficulty: 中等
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/3700-3799/3765.Complete%20Prime%20Number/README.md
+---
+
+<!-- problem:start -->
+
+# [3765. 完全质数](https://leetcode.cn/problems/complete-prime-number)
+
+[English Version](/solution/3700-3799/3765.Complete%20Prime%20Number/README_EN.md)
+
+## 题目描述
+
+<!-- description:start -->
+
+<p>给你一个整数 <code>num</code>。</p>
+
+<p>如果一个数 <code>num</code> 的每一个 <strong>前缀</strong> 和每一个 <strong>后缀</strong> 都是 <strong>质数</strong>，则称该数为 <strong>完全质数</strong>。</p>
+
+<p>如果 <code>num</code> 是完全质数，返回 <code>true</code>，否则返回 <code>false</code>。</p>
+
+<p><strong>注意</strong>：</p>
+
+<ul>
+	<li>一个数的 <strong>前缀</strong> 是由该数的 <strong>前</strong> <code>k</code> 位数字构成的。</li>
+	<li>一个数的 <strong>后缀</strong> 是由该数的 <strong>后</strong> <code>k</code> 位数字构成的。</li>
+	<li><strong>质数</strong> 是大于 1 且只有两个因子（1 和它本身）的自然数。</li>
+	<li>个位数只有在它是 <strong>质数</strong> 时才被视为完全质数。</li>
+</ul>
+
+<p>&nbsp;</p>
+
+<p><strong class="example">示例 1：</strong></p>
+
+<div class="example-block">
+<p><strong>输入：</strong><span class="example-io">num = 23</span></p>
+
+<p><strong>输出：</strong><span class="example-io">true</span></p>
+
+<p><strong>解释：</strong></p>
+
+<ul>
+	<li><code>num = 23</code> 的前缀是 2 和 23，它们都是质数。</li>
+	<li><code>num = 23</code> 的后缀是 3 和 23，它们都是质数。</li>
+	<li>所有的前缀和后缀都是质数，所以 23 是完全质数，答案是 <code>true</code>。</li>
+</ul>
+</div>
+
+<p><strong class="example">示例 2：</strong></p>
+
+<div class="example-block">
+<p><strong>输入：</strong><span class="example-io">num = 39</span></p>
+
+<p><strong>输出：</strong><span class="example-io">false</span></p>
+
+<p><strong>解释：</strong></p>
+
+<ul>
+	<li><code>num = 39</code> 的前缀是 3 和 39。3 是质数，但 39 不是质数。</li>
+	<li><code>num = 39</code> 的后缀是 9 和 39。9 和 39 都不是质数。</li>
+	<li>至少有一个前缀或后缀不是质数，所以 39 不是完全质数，答案是 <code>false</code>。</li>
+</ul>
+</div>
+
+<p><strong class="example">示例 3：</strong></p>
+
+<div class="example-block">
+<p><strong>输入：</strong><span class="example-io">num = 7</span></p>
+
+<p><strong>输出：</strong><span class="example-io">true</span></p>
+
+<p><strong>解释：</strong></p>
+
+<ul>
+	<li>7 是质数，所以它的所有前缀和后缀都是质数，答案是 <code>true</code>。</li>
+</ul>
+</div>
+
+<p>&nbsp;</p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>1 &lt;= num &lt;= 10<sup>9</sup></code></li>
+</ul>
+
+<!-- description:end -->
+
+## 解法
+
+<!-- solution:start -->
+
+### 方法一
+
+<!-- tabs:start -->
+
+#### Python3
+
+```python
+
+```
+
+#### Java
+
+```java
+
+```
+
+#### C++
+
+```cpp
+
+```
+
+#### Go
+
+```go
+
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
+<!-- problem:end -->

solution/3700-3799/3765.Complete Prime Number/README_EN.md

@@ -0,0 +1,124 @@
+---
+comments: true
+difficulty: Medium
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/3700-3799/3765.Complete%20Prime%20Number/README_EN.md
+---
+
+<!-- problem:start -->
+
+# [3765. Complete Prime Number](https://leetcode.com/problems/complete-prime-number)
+
+[中文文档](/solution/3700-3799/3765.Complete%20Prime%20Number/README.md)
+
+## Description
+
+<!-- description:start -->
+
+<p>You are given an integer <code>num</code>.</p>
+
+<p>A number <code>num</code> is called a <strong>Complete Prime Number</strong> if every <strong>prefix</strong> and every <strong>suffix</strong> of <code>num</code> is <strong>prime</strong>.</p>
+
+<p>Return <code>true</code> if <code>num</code> is a Complete Prime Number, otherwise return <code>false</code>.</p>
+
+<p><strong>Note</strong>:</p>
+
+<ul>
+	<li>A <strong>prefix</strong> of a number is formed by the <strong>first</strong> <code>k</code> digits of the number.</li>
+	<li>A <strong>suffix</strong> of a number is formed by the <strong>last</strong> <code>k</code> digits of the number.</li>
+	<li>A <strong>prime</strong> number is a natural number greater than 1 with only two factors, 1 and itself.</li>
+	<li>Single-digit numbers are considered Complete Prime Numbers only if they are <strong>prime</strong>.</li>
+</ul>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num = 23</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">true</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li><strong>​​​​​​​</strong>Prefixes of <code>num = 23</code> are 2 and 23, both are prime.</li>
+	<li>Suffixes of <code>num = 23</code> are 3 and 23, both are prime.</li>
+	<li>All prefixes and suffixes are prime, so 23 is a Complete Prime Number and the answer is <code>true</code>.</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num = 39</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">false</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li>Prefixes of <code>num = 39</code> are 3 and 39. 3 is prime, but 39 is not prime.</li>
+	<li>Suffixes of <code>num = 39</code> are 9 and 39. Both 9 and 39 are not prime.</li>
+	<li>At least one prefix or suffix is not prime, so 39 is not a Complete Prime Number and the answer is <code>false</code>.</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num = 7</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">true</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li>7 is prime, so all its prefixes and suffixes are prime and the answer is <code>true</code>.</li>
+</ul>
+</div>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= num &lt;= 10<sup>9</sup></code></li>
+</ul>
+
+<!-- description:end -->
+
+## Solutions
+
+<!-- solution:start -->
+
+### Solution 1
+
+<!-- tabs:start -->
+
+#### Python3
+
+```python
+
+```
+
+#### Java
+
+```java
+
+```
+
+#### C++
+
+```cpp
+
+```
+
+#### Go
+
+```go
+
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
+<!-- problem:end -->