Update formatting in explanations and fix solution 3643

Author: romankurnovskii

explanations/3643/en.md

@@ -42,9 +42,9 @@ We iterate i from 0 to k//2 - 1 (i.e., 0 to 0 for k=3).
 
 **2.3 Trace Walkthrough:**
 
-| i | top | bottom | Before Swap | After Swap |
-|---|-----|--------|-------------|------------|
-| 0 | 1 | 3 | grid[1][0:3] = [5,6,7]<br>grid[3][0:3] = [13,14,15] | grid[1][0:3] = [13,14,15]<br>grid[3][0:3] = [5,6,7] |
+| i   | top | bottom | Before Swap                                         | After Swap                                          |
+| --- | --- | ------ | --------------------------------------------------- | --------------------------------------------------- |
+| 0   | 1   | 3      | grid[1][0:3] = [5,6,7]<br>grid[3][0:3] = [13,14,15] | grid[1][0:3] = [13,14,15]<br>grid[3][0:3] = [5,6,7] |
 
 **2.4 Increment and Loop:**
 
@@ -53,4 +53,3 @@ After swapping, the grid becomes: `[[1,2,3,4],[13,14,15,8],[9,10,11,12],[5,6,7,1
 **2.5 Return Result:**
 
 The result is the grid with the submatrix flipped vertically: `[[1,2,3,4],[13,14,15,8],[9,10,11,12],[5,6,7,16]]`
-

explanations/3698/en.md

@@ -43,13 +43,14 @@ We expand both pointers while maintaining strict increase/decrease.
 
 **2.3 Trace Walkthrough:**
 
-| Step | Action | l | r | lsum | rsum | nums[l] | nums[r] |
-|------|--------|---|---|------|------|---------|---------|
-| 1 | Expand left (1<3) | 0→1 | 2 | 1 | 0 | 3 | 2 |
-| 2 | Expand right (3>2) | 1 | 2→1 | 1 | 2 | 3 | 3 |
-| 3 | Pointers meet | 1 | 1 | 1 | 2 | 3 | 3 |
+| Step | Action             | l   | r   | lsum | rsum | nums[l] | nums[r] |
+| ---- | ------------------ | --- | --- | ---- | ---- | ------- | ------- |
+| 1    | Expand left (1<3)  | 0→1 | 2   | 1    | 0    | 3       | 2       |
+| 2    | Expand right (3>2) | 1   | 2→1 | 1    | 2    | 3       | 3       |
+| 3    | Pointers meet      | 1   | 1   | 1    | 2    | 3       | 3       |
 
 Since l==r, we have a single peak. Try both options:
+
 - Option 1: lsum + nums[l] = 1+3=4, rsum=2, diff=|4-2|=2
 - Option 2: lsum=1, rsum + nums[r]=2+3=5, diff=|1-5|=4
 - Minimum: 2
@@ -61,4 +62,3 @@ The algorithm handles all cases: single peak, flat peak, or invalid.
 **2.5 Return Result:**
 
 The result is 2, the minimum absolute difference.
-

solutions/3643/01.py

@@ -1,12 +1,13 @@
 class Solution:
-    def reverseSubmatrix(self, grid: List[List[int]], x: int, y: int, k: int) -> List[List[int]]:
+    def reverseSubmatrix(
+        self, grid: List[List[int]], x: int, y: int, k: int
+    ) -> List[List[int]]:
         # Swap corresponding rows within the k×k block
         for i in range(k // 2):
             top = x + i
             bottom = x + k - 1 - i
-            grid[top][y:y + k], grid[bottom][y:y + k] = (
-                grid[bottom][y:y + k],
-                grid[top][y:y + k],
+            grid[top][y : y + k], grid[bottom][y : y + k] = (
+                grid[bottom][y : y + k],
+                grid[top][y : y + k],
             )
         return grid
-