diff --git a/solution/3000-3099/3019.Number of Changing Keys/README.md b/solution/3000-3099/3019.Number of Changing Keys/README.md index 065a79f073985..f4185f581cf1f 100644 --- a/solution/3000-3099/3019.Number of Changing Keys/README.md +++ b/solution/3000-3099/3019.Number of Changing Keys/README.md @@ -31,7 +31,7 @@ tags: 
 输入：s = "aAbBcC"
 输出：2
-解释：
+解释： 
 从 s[0] = 'a' 到 s[1] = 'A'，不存在按键变更，因为不计入 caps lock 或 shift 。
 从 s[1] = 'A' 到 s[2] = 'b'，按键变更。
 从 s[2] = 'b' 到 s[3] = 'B'，不存在按键变更，因为不计入 caps lock 或 shift 。
diff --git a/solution/3000-3099/3019.Number of Changing Keys/README_EN.md b/solution/3000-3099/3019.Number of Changing Keys/README_EN.md
index 40d4ccdb81352..dab3135859c5e 100644
--- a/solution/3000-3099/3019.Number of Changing Keys/README_EN.md	
+++ b/solution/3000-3099/3019.Number of Changing Keys/README_EN.md	
@@ -30,7 +30,7 @@ tags:
 
 Input: s = "aAbBcC"
 Output: 2
-Explanation:
+Explanation: 
 From s[0] = 'a' to s[1] = 'A', there is no change of key as caps lock or shift is not counted.
 From s[1] = 'A' to s[2] = 'b', there is a change of key.
 From s[2] = 'b' to s[3] = 'B', there is no change of key as caps lock or shift is not counted.
diff --git a/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README.md b/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README.md
new file mode 100644
index 0000000000000..401c3920d8ce7
--- /dev/null
+++ b/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README.md	
@@ -0,0 +1,104 @@
+---
+comments: true
+difficulty: 困难
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README.md
+---
+
+
+
+# [3416. Subsequences with a Unique Middle Mode II 🔒](https://leetcode.cn/problems/subsequences-with-a-unique-middle-mode-ii)
+
+[English Version](/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README_EN.md)
+
+## 题目描述
+
+
+
+
Given an integer array nums, find the number of subsequences of size 5 of nums with a unique middle mode.

+
+
Since the answer may be very large, return it modulo 109 + 7.

+
+
A mode of a sequence of numbers is defined as the element that appears the maximum number of times in the sequence.

+
+
A sequence of numbers contains a unique mode if it has only one mode.

+
+
A sequence of numbers seq of size 5 contains a unique middle mode if the middle element (seq[2]) is a unique mode.

+
+
 

+
Example 1:

+
+
Input: nums = [1,1,1,1,1,1]

+
+
Output: 6

+
+
Explanation:

+
+
[1, 1, 1, 1, 1] is the only subsequence of size 5 that can be formed from this list, and it has a unique middle mode of 1.

+
+
Example 2:

+
+
Input: nums = [1,2,2,3,3,4]

+
+
Output: 4

+
+
Explanation:

+
+
[1, 2, 2, 3, 4] and [1, 2, 3, 3, 4] have unique middle modes because the number at index 2 has the greatest frequency in the subsequence. [1, 2, 2, 3, 3] does not have a unique middle mode because 2 and 3 both appear twice in the subsequence.

+
+
Example 3:

+
+
Input: nums = [0,1,2,3,4,5,6,7,8]

+
+
Output: 0

+
+
Explanation:

+
+
There does not exist a subsequence of length 5 with a unique middle mode.

+
+
 

+
Constraints:

+
+
+
+
+
+## 解法
+
+
+
+### 方法一
+
+
+
+#### Python3
+
+```python
+
+```
+
+#### Java
+
+```java
+
+```
+
+#### C++
+
+```cpp
+
+```
+
+#### Go
+
+```go
+
+```
+
+
+
+
+
+
diff --git a/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README_EN.md b/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README_EN.md
new file mode 100644
index 0000000000000..265e95e1ffc0e
--- /dev/null
+++ b/solution/3400-3499/3416.Subsequences with a Unique Middle Mode II/README_EN.md	
@@ -0,0 +1,104 @@
+---
+comments: true
+difficulty: Hard
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README_EN.md
+---
+
+
+
+# [3416. Subsequences with a Unique Middle Mode II 🔒](https://leetcode.com/problems/subsequences-with-a-unique-middle-mode-ii)
+
+[中文文档](/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README.md)
+
+## Description
+
+
+
+
Given an integer array nums, find the number of subsequences of size 5 of nums with a unique middle mode.

+
+
Since the answer may be very large, return it modulo 109 + 7.

+
+
A mode of a sequence of numbers is defined as the element that appears the maximum number of times in the sequence.

+
+
A sequence of numbers contains a unique mode if it has only one mode.

+
+
A sequence of numbers seq of size 5 contains a unique middle mode if the middle element (seq[2]) is a unique mode.

+
+
 

+
Example 1:

+
+
Input: nums = [1,1,1,1,1,1]

+
+
Output: 6

+
+
Explanation:

+
+
[1, 1, 1, 1, 1] is the only subsequence of size 5 that can be formed from this list, and it has a unique middle mode of 1.

+
+
Example 2:

+
+
Input: nums = [1,2,2,3,3,4]

+
+
Output: 4

+
+
Explanation:

+
+
[1, 2, 2, 3, 4] and [1, 2, 3, 3, 4] have unique middle modes because the number at index 2 has the greatest frequency in the subsequence. [1, 2, 2, 3, 3] does not have a unique middle mode because 2 and 3 both appear twice in the subsequence.

+
+
Example 3:

+
+
Input: nums = [0,1,2,3,4,5,6,7,8]

+
+
Output: 0

+
+
Explanation:

+
+
There does not exist a subsequence of length 5 with a unique middle mode.

+
+
 

+
Constraints:

+
+
+
+
+
+## Solutions
+
+
+
+### Solution 1
+
+
+
+#### Python3
+
+```python
+
+```
+
+#### Java
+
+```java
+
+```
+
+#### C++
+
+```cpp
+
+```
+
+#### Go
+
+```go
+
+```
+
+
+
+
+
+
diff --git a/solution/README.md b/solution/README.md
index e4f959a807387..62cb9e9a55bcc 100644
--- a/solution/README.md
+++ b/solution/README.md
@@ -3426,6 +3426,7 @@
 |  3413  |  [收集连续 K 个袋子可以获得的最多硬币数量](/solution/3400-3499/3413.Maximum%20Coins%20From%20K%20Consecutive%20Bags/README.md)  |    |  中等  |  第 431 场周赛  |
 |  3414  |  [不重叠区间的最大得分](/solution/3400-3499/3414.Maximum%20Score%20of%20Non-overlapping%20Intervals/README.md)  |    |  困难  |  第 431 场周赛  |
 |  3415  |  [Find Products with Three Consecutive Digits](/solution/3400-3499/3415.Find%20Products%20with%20Three%20Consecutive%20Digits/README.md)  |    |  简单  |  🔒  |
+|  3416  |  [Subsequences with a Unique Middle Mode II](/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README.md)  |    |  困难  |  🔒  |
 
 ## 版权
 
diff --git a/solution/README_EN.md b/solution/README_EN.md
index 13c7c285e4134..91fa8215b0265 100644
--- a/solution/README_EN.md
+++ b/solution/README_EN.md
@@ -3424,6 +3424,7 @@ Press Control + F(or Command + F on
 |  3413  |  [Maximum Coins From K Consecutive Bags](/solution/3400-3499/3413.Maximum%20Coins%20From%20K%20Consecutive%20Bags/README_EN.md)  |    |  Medium  |  Weekly Contest 431  |
 |  3414  |  [Maximum Score of Non-overlapping Intervals](/solution/3400-3499/3414.Maximum%20Score%20of%20Non-overlapping%20Intervals/README_EN.md)  |    |  Hard  |  Weekly Contest 431  |
 |  3415  |  [Find Products with Three Consecutive Digits](/solution/3400-3499/3415.Find%20Products%20with%20Three%20Consecutive%20Digits/README_EN.md)  |    |  Easy  |  🔒  |
+|  3416  |  [Subsequences with a Unique Middle Mode II](/solution/3400-3499/3416.Subsequences%20with%20a%20Unique%20Middle%20Mode%20II/README_EN.md)  |    |  Hard  |  🔒  |
 
 ## Copyright