feat: add solutions to lc problems: No.3642,3643

solution/3600-3699/3642.Find Books with Polarized Opinions/README.md

@@ -167,14 +167,94 @@ Each row represents a reading session where someone read a portion of a book. se
 
 <!-- solution:start -->
 
-### 方法一
+### 方法一：连接 + 分组聚合
+
+我们可以通过连接 `books` 表和 `reading_sessions` 表，然后对结果进行分组和聚合来实现。
+
+首先，我们需要计算每本书的评分范围、极端评分的数量和极端评分的比例。
+
+然后，我们可以根据这些指标筛选出符合条件的书籍。
+
+最后，按照极端评分比例和书名的降序排列结果。
 
 <!-- tabs:start -->
 
 #### MySQL
 
 ```sql
+# Write your MySQL query statement below
+SELECT
+    book_id,
+    title,
+    author,
+    genre,
+    pages,
+    (MAX(session_rating) - MIN(session_rating)) AS rating_spread,
+    ROUND((SUM(session_rating <= 2) + SUM(session_rating >= 4)) / COUNT(1), 2) polarization_score
+FROM
+    books
+    JOIN reading_sessions USING (book_id)
+GROUP BY book_id
+HAVING
+    COUNT(1) >= 5
+    AND MAX(session_rating) >= 4
+    AND MIN(session_rating) <= 2
+    AND polarization_score >= 0.6
+ORDER BY polarization_score DESC, title DESC;
+```
 
+#### Pandas
+
+```python
+import pandas as pd
+from decimal import Decimal, ROUND_HALF_UP
+
+
+def find_polarized_books(
+    books: pd.DataFrame, reading_sessions: pd.DataFrame
+) -> pd.DataFrame:
+    df = books.merge(reading_sessions, on="book_id")
+    agg_df = (
+        df.groupby(["book_id", "title", "author", "genre", "pages"])
+        .agg(
+            max_rating=("session_rating", "max"),
+            min_rating=("session_rating", "min"),
+            rating_spread=("session_rating", lambda x: x.max() - x.min()),
+            count_sessions=("session_rating", "count"),
+            low_or_high_count=("session_rating", lambda x: ((x <= 2) | (x >= 4)).sum()),
+        )
+        .reset_index()
+    )
+
+    agg_df["polarization_score"] = agg_df.apply(
+        lambda r: float(
+            Decimal(r["low_or_high_count"] / r["count_sessions"]).quantize(
+                Decimal("0.01"), rounding=ROUND_HALF_UP
+            )
+        ),
+        axis=1,
+    )
+
+    result = agg_df[
+        (agg_df["count_sessions"] >= 5)
+        & (agg_df["max_rating"] >= 4)
+        & (agg_df["min_rating"] <= 2)
+        & (agg_df["polarization_score"] >= 0.6)
+    ]
+
+    return result.sort_values(
+        by=["polarization_score", "title"], ascending=[False, False]
+    )[
+        [
+            "book_id",
+            "title",
+            "author",
+            "genre",
+            "pages",
+            "rating_spread",
+            "polarization_score",
+        ]
+    ]
 ```
 
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solution/3600-3699/3642.Find Books with Polarized Opinions/README_EN.md

@@ -167,14 +167,94 @@ Each row represents a reading session where someone read a portion of a book. se
 
 <!-- solution:start -->
 
-### Solution 1
+### Solution 1: Join + Group Aggregation
+
+We can implement this by joining the `books` table with the `reading_sessions` table, then grouping and aggregating the results.
+
+First, we need to calculate the rating range, the number of extreme ratings, and the proportion of extreme ratings for each book.
+
+Then, we can filter out books that meet the criteria based on these metrics.
+
+Finally, sort the results by extreme rating proportion and book title in descending order.
 
 <!-- tabs:start -->
 
 #### MySQL
 
 ```sql
+# Write your MySQL query statement below
+SELECT
+    book_id,
+    title,
+    author,
+    genre,
+    pages,
+    (MAX(session_rating) - MIN(session_rating)) AS rating_spread,
+    ROUND((SUM(session_rating <= 2) + SUM(session_rating >= 4)) / COUNT(1), 2) polarization_score
+FROM
+    books
+    JOIN reading_sessions USING (book_id)
+GROUP BY book_id
+HAVING
+    COUNT(1) >= 5
+    AND MAX(session_rating) >= 4
+    AND MIN(session_rating) <= 2
+    AND polarization_score >= 0.6
+ORDER BY polarization_score DESC, title DESC;
+```
 
+#### Pandas
+
+```python
+import pandas as pd
+from decimal import Decimal, ROUND_HALF_UP
+
+
+def find_polarized_books(
+    books: pd.DataFrame, reading_sessions: pd.DataFrame
+) -> pd.DataFrame:
+    df = books.merge(reading_sessions, on="book_id")
+    agg_df = (
+        df.groupby(["book_id", "title", "author", "genre", "pages"])
+        .agg(
+            max_rating=("session_rating", "max"),
+            min_rating=("session_rating", "min"),
+            rating_spread=("session_rating", lambda x: x.max() - x.min()),
+            count_sessions=("session_rating", "count"),
+            low_or_high_count=("session_rating", lambda x: ((x <= 2) | (x >= 4)).sum()),
+        )
+        .reset_index()
+    )
+
+    agg_df["polarization_score"] = agg_df.apply(
+        lambda r: float(
+            Decimal(r["low_or_high_count"] / r["count_sessions"]).quantize(
+                Decimal("0.01"), rounding=ROUND_HALF_UP
+            )
+        ),
+        axis=1,
+    )
+
+    result = agg_df[
+        (agg_df["count_sessions"] >= 5)
+        & (agg_df["max_rating"] >= 4)
+        & (agg_df["min_rating"] <= 2)
+        & (agg_df["polarization_score"] >= 0.6)
+    ]
+
+    return result.sort_values(
+        by=["polarization_score", "title"], ascending=[False, False]
+    )[
+        [
+            "book_id",
+            "title",
+            "author",
+            "genre",
+            "pages",
+            "rating_spread",
+            "polarization_score",
+        ]
+    ]
 ```
 
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solution/3600-3699/3642.Find Books with Polarized Opinions/Solution.py

@@ -0,0 +1,49 @@
+import pandas as pd
+from decimal import Decimal, ROUND_HALF_UP
+
+
+def find_polarized_books(
+    books: pd.DataFrame, reading_sessions: pd.DataFrame
+) -> pd.DataFrame:
+    df = books.merge(reading_sessions, on="book_id")
+    agg_df = (
+        df.groupby(["book_id", "title", "author", "genre", "pages"])
+        .agg(
+            max_rating=("session_rating", "max"),
+            min_rating=("session_rating", "min"),
+            rating_spread=("session_rating", lambda x: x.max() - x.min()),
+            count_sessions=("session_rating", "count"),
+            low_or_high_count=("session_rating", lambda x: ((x <= 2) | (x >= 4)).sum()),
+        )
+        .reset_index()
+    )
+
+    agg_df["polarization_score"] = agg_df.apply(
+        lambda r: float(
+            Decimal(r["low_or_high_count"] / r["count_sessions"]).quantize(
+                Decimal("0.01"), rounding=ROUND_HALF_UP
+            )
+        ),
+        axis=1,
+    )
+
+    result = agg_df[
+        (agg_df["count_sessions"] >= 5)
+        & (agg_df["max_rating"] >= 4)
+        & (agg_df["min_rating"] <= 2)
+        & (agg_df["polarization_score"] >= 0.6)
+    ]
+
+    return result.sort_values(
+        by=["polarization_score", "title"], ascending=[False, False]
+    )[
+        [
+            "book_id",
+            "title",
+            "author",
+            "genre",
+            "pages",
+            "rating_spread",
+            "polarization_score",
+        ]
+    ]

solution/3600-3699/3642.Find Books with Polarized Opinions/Solution.sql

@@ -0,0 +1,19 @@
+# Write your MySQL query statement below
+SELECT
+    book_id,
+    title,
+    author,
+    genre,
+    pages,
+    (MAX(session_rating) - MIN(session_rating)) AS rating_spread,
+    ROUND((SUM(session_rating <= 2) + SUM(session_rating >= 4)) / COUNT(1), 2) polarization_score
+FROM
+    books
+    JOIN reading_sessions USING (book_id)
+GROUP BY book_id
+HAVING
+    COUNT(1) >= 5
+    AND MAX(session_rating) >= 4
+    AND MIN(session_rating) <= 2
+    AND polarization_score >= 0.6
+ORDER BY polarization_score DESC, title DESC;

solution/3600-3699/3643.Flip Square Submatrix Vertically/README.md

@@ -68,32 +68,95 @@ edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3643.Fl
 
 <!-- solution:start -->
 
-### 方法一
+### 方法一：模拟
+
+我们从第 $x$ 行开始，一共翻转 $\lfloor \frac{k}{2} \rfloor$ 行。
+
+对于每一行 $i$，我们需要将其与对应的行 $i_2$ 进行交换，其中 $i_2 = x + k - 1 - (i - x)$。
+
+在交换时，我们需要遍历 $j \in [y, y + k)$，将 $\text{grid}[i][j]$ 和 $\text{grid}[i_2][j]$ 进行交换。
+
+最后，返回更新后的矩阵。
+
+时间复杂度 $O(k^2)$，其中 $k$ 是子矩阵的边长。空间复杂度 $O(1)$。
 
 <!-- tabs:start -->
 
 #### Python3
 
 ```python
-
+class Solution:
+    def reverseSubmatrix(
+        self, grid: List[List[int]], x: int, y: int, k: int
+    ) -> List[List[int]]:
+        for i in range(x, x + k // 2):
+            i2 = x + k - 1 - (i - x)
+            for j in range(y, y + k):
+                grid[i][j], grid[i2][j] = grid[i2][j], grid[i][j]
+        return grid
 ```
 
 #### Java
 
 ```java
-
+class Solution {
+    public int[][] reverseSubmatrix(int[][] grid, int x, int y, int k) {
+        for (int i = x; i < x + k / 2; i++) {
+            int i2 = x + k - 1 - (i - x);
+            for (int j = y; j < y + k; j++) {
+                int t = grid[i][j];
+                grid[i][j] = grid[i2][j];
+                grid[i2][j] = t;
+            }
+        }
+        return grid;
+    }
+}
 ```
 
 #### C++
 
 ```cpp
-
+class Solution {
+public:
+    vector<vector<int>> reverseSubmatrix(vector<vector<int>>& grid, int x, int y, int k) {
+        for (int i = x; i < x + k / 2; i++) {
+            int i2 = x + k - 1 - (i - x);
+            for (int j = y; j < y + k; j++) {
+                swap(grid[i][j], grid[i2][j]);
+            }
+        }
+        return grid;
+    }
+};
 ```
 
 #### Go
 
 ```go
+func reverseSubmatrix(grid [][]int, x int, y int, k int) [][]int {
+	for i := x; i < x+k/2; i++ {
+		i2 := x + k - 1 - (i - x)
+		for j := y; j < y+k; j++ {
+			grid[i][j], grid[i2][j] = grid[i2][j], grid[i][j]
+		}
+	}
+	return grid
+}
+```
 
+#### TypeScript
+
+```ts
+function reverseSubmatrix(grid: number[][], x: number, y: number, k: number): number[][] {
+    for (let i = x; i < x + Math.floor(k / 2); i++) {
+        const i2 = x + k - 1 - (i - x);
+        for (let j = y; j < y + k; j++) {
+            [grid[i][j], grid[i2][j]] = [grid[i2][j], grid[i][j]];
+        }
+    }
+    return grid;
+}
 ```
 
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