docs(content): revamp sliding-window examples and purge empty appendix pages

apps/docs/content/(01-linear-structures)/sliding-window/index.mdx

@@ -48,18 +48,14 @@ The window size never changes. The main task is updating the window state effici
 
 
 ```python
-def fixed_window(nums, k):
+def sliding_window_fixed(input, window_size):
-    window_sum = 0
+    ans = window = input[0:window_size]
-    best = float('-inf')
+    for right in range(window_size, len(input)):
-
+        left = right - window_size
-    for right in range(len(nums)):
+        remove input[left] from window
-        window_sum += nums[right]            # add the new element
+        append input[right] to window
-
+        ans = optimal(ans, window)
-        if right >= k - 1:                   # window is full
+    return ans
-            best = max(best, window_sum)     # record answer
-            window_sum -= nums[right - k + 1]  # remove the oldest element
-
-    return best
 ```
 
 <Steps>
@@ -87,24 +83,43 @@ Here the window expands until invalid, then shrinks until valid again.
 
 </Frame>
 
+
+<Tabs inline>
+  <Tab title="Longest Window">
+
 ```python
-def flexible_window(nums, target):
+def sliding_window_flexible_longest(input):
+    initialize window, ans
     left = 0
-    window_sum = 0
+    for right in range(len(input)):
-    best = 0
+        append input[right] to window
-
+        while invalid(window):        # update left until window is valid again
-    for right in range(len(nums)):
+            remove input[left] from window
-        window_sum += nums[right]            # grow the window
-
-        while window_sum > target:           # window is invalid
-            window_sum -= nums[left]         # shrink from the left
             left += 1
+        ans = max(ans, window)        # window is guaranteed to be valid here
+    return ans
 
-        best = max(best, right - left + 1)   # window is valid, record answer
-
-    return best
 ```
 
+  </Tab>
+  <Tab title="Shortest Window">
+
+```python
+def sliding_window_flexible_shortest(input):
+    initialize window, ans
+    left = 0
+    for right in range(len(input)):
+        append input[right] to window
+        while valid(window):
+            ans = min(ans, window)      # window is guaranteed to be valid here
+            remove input[left] from window
+            left += 1
+    return ans
+```
+
+  </Tab>
+</Tabs>
+
 <Steps>
   <Step title="">
   Add `nums[right]` to the window.
@@ -119,26 +134,6 @@ def flexible_window(nums, target):
 
 ---
 
-For "shortest window" problems, swap the logic: use `while` for the *valid* case, record the answer inside the loop, then shrink.
-
-```python
-def shortest_valid_window(nums, target):
-    left = 0
-    window_sum = 0
-    best = float('inf')
-
-    for right in range(len(nums)):
-        window_sum += nums[right]
-
-        while window_sum >= target:          # window is valid
-            best = min(best, right - left + 1)   # record, then try to shrink
-            window_sum -= nums[left]
-            left += 1
-
-    return best if best != float('inf') else 0
-
-```
-
 ## 3. Frequency-tracking windows
 
 :::tip

apps/docs/content/appendix/(1-data-structures)/array.mdx

@@ -1,11 +0,0 @@
----
-title: "Array"
-list: "https://leetcode.com/problem-list/array/"
-icon: list-ordered
-sidebar:
-  badge: '48'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Array.
-:::

apps/docs/content/appendix/(1-data-structures)/binary-tree.mdx

@@ -1,11 +0,0 @@
----
-title: "Binary Tree"
-list: "https://leetcode.com/problem-list/binary-tree/"
-icon: git-branch
-sidebar:
-  badge: '9'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Binary Tree.
-:::

apps/docs/content/appendix/(1-data-structures)/directed-acyclic-graph.mdx

@@ -1,11 +0,0 @@
----
-title: "Directed Acyclic Graph"
-list: "https://leetcode.com/problem-list/directed-acyclic-graph/"
-icon: route
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Directed Acyclic Graph.
-:::

apps/docs/content/appendix/(1-data-structures)/doubly-linked-list.mdx

@@ -1,11 +0,0 @@
----
-title: "Doubly-Linked List"
-list: "https://leetcode.com/problem-list/doubly-linked-list/"
-icon: link-2
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Doubly-Linked List.
-:::

apps/docs/content/appendix/(1-data-structures)/graph.mdx

@@ -1,11 +0,0 @@
----
-title: "Graph Theory"
-list: "https://leetcode.com/problem-list/graph/"
-icon: share-2
-sidebar:
-  badge: '5'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Graph Theory.
-:::

apps/docs/content/appendix/(1-data-structures)/k-d-tree.mdx

@@ -1,11 +0,0 @@
----
-title: "K-D Tree"
-list: "https://leetcode.com/problem-list/k-d-tree/"
-icon: axis-3d
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged K-D Tree.
-:::

apps/docs/content/appendix/(1-data-structures)/meta.ts

@@ -1,3 +0,0 @@
-import { defineMeta } from "blume";
-
-export default defineMeta({ title: "Data Structures", order: 1 });

apps/docs/content/appendix/(1-data-structures)/queue.mdx

@@ -1,11 +0,0 @@
----
-title: "Queue"
-list: "https://leetcode.com/problem-list/queue/"
-icon: list-end
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Queue.
-:::

apps/docs/content/appendix/(1-data-structures)/string.mdx

@@ -1,11 +0,0 @@
----
-title: "String"
-list: "https://leetcode.com/problem-list/string/"
-icon: quote
-sidebar:
-  badge: '18'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged String.
-:::

apps/docs/content/appendix/(1-data-structures)/tree.mdx

@@ -1,11 +0,0 @@
----
-title: "Tree"
-list: "https://leetcode.com/problem-list/tree/"
-icon: tree-deciduous
-sidebar:
-  badge: '9'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Tree.
-:::

apps/docs/content/appendix/(2-algorithms)/bidirectional-search.mdx

@@ -1,11 +0,0 @@
----
-title: "Bidirectional Search"
-list: "https://leetcode.com/problem-list/bidirectional-search/"
-icon: move-horizontal
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Bidirectional Search.
-:::

apps/docs/content/appendix/(2-algorithms)/binary-lifting.mdx

@@ -1,11 +0,0 @@
----
-title: "Binary Lifting"
-list: "https://leetcode.com/problem-list/binary-lifting/"
-icon: chevrons-up
-sidebar:
-  badge: '2'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Binary Lifting.
-:::

apps/docs/content/appendix/(2-algorithms)/bit-manipulation.mdx

@@ -1,11 +0,0 @@
----
-title: "Bit Manipulation"
-list: "https://leetcode.com/problem-list/bit-manipulation/"
-icon: binary
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Bit Manipulation.
-:::

apps/docs/content/appendix/(2-algorithms)/bracket-sequences.mdx

@@ -1,11 +0,0 @@
----
-title: "Bracket Sequences"
-list: "https://leetcode.com/problem-list/bracket-sequences/"
-icon: parentheses
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Bracket Sequences.
-:::

apps/docs/content/appendix/(2-algorithms)/bucket-sort.mdx

@@ -1,11 +0,0 @@
----
-title: "Bucket Sort"
-list: "https://leetcode.com/problem-list/bucket-sort/"
-icon: container
-sidebar:
-  badge: '2'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Bucket Sort.
-:::

apps/docs/content/appendix/(2-algorithms)/complete-knapsack.mdx

@@ -1,11 +0,0 @@
----
-title: "Complete Knapsack"
-list: "https://leetcode.com/problem-list/complete-knapsack/"
-icon: package-plus
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Complete Knapsack.
-:::

apps/docs/content/appendix/(2-algorithms)/divide-and-conquer.mdx

@@ -1,11 +0,0 @@
----
-title: "Divide and Conquer"
-list: "https://leetcode.com/problem-list/divide-and-conquer/"
-icon: split
-sidebar:
-  badge: '5'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Divide and Conquer.
-:::

apps/docs/content/appendix/(2-algorithms)/floyds-cycle-finding-algorithm.mdx

@@ -1,11 +0,0 @@
----
-title: "Floyd's Cycle Finding Algorithm"
-list: "https://leetcode.com/problem-list/floyds-cycle-finding-algorithm/"
-icon: repeat
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Floyd's Cycle Finding Algorithm.
-:::

apps/docs/content/appendix/(2-algorithms)/knapsack-problem.mdx

@@ -1,11 +0,0 @@
----
-title: "Knapsack Problem"
-list: "https://leetcode.com/problem-list/knapsack-problem/"
-icon: backpack
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Knapsack Problem.
-:::

apps/docs/content/appendix/(2-algorithms)/longest-common-subsequence.mdx

@@ -1,11 +0,0 @@
----
-title: "Longest Common Subsequence"
-list: "https://leetcode.com/problem-list/longest-common-subsequence/"
-icon: diff
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Longest Common Subsequence.
-:::

apps/docs/content/appendix/(2-algorithms)/lowest-common-ancestor.mdx

@@ -1,11 +0,0 @@
----
-title: "Lowest Common Ancestor"
-list: "https://leetcode.com/problem-list/lowest-common-ancestor/"
-icon: git-merge
-sidebar:
-  badge: '2'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Lowest Common Ancestor.
-:::

apps/docs/content/appendix/(2-algorithms)/memoization.mdx

@@ -1,11 +0,0 @@
----
-title: "Memoization"
-list: "https://leetcode.com/problem-list/memoization/"
-icon: database
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Memoization.
-:::

apps/docs/content/appendix/(2-algorithms)/merge-sort.mdx

@@ -1,11 +0,0 @@
----
-title: "Merge Sort"
-list: "https://leetcode.com/problem-list/merge-sort/"
-icon: blend
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Merge Sort.
-:::

apps/docs/content/appendix/(2-algorithms)/meta.ts

@@ -1,3 +0,0 @@
-import { defineMeta } from "blume";
-
-export default defineMeta({ title: "Algorithms", order: 2 });

apps/docs/content/appendix/(2-algorithms)/quickselect.mdx

@@ -1,11 +0,0 @@
----
-title: "Quickselect"
-list: "https://leetcode.com/problem-list/quickselect/"
-icon: crosshair
-sidebar:
-  badge: '3'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Quickselect.
-:::

apps/docs/content/appendix/(2-algorithms)/quicksort.mdx

@@ -1,11 +0,0 @@
----
-title: "Quicksort"
-icon: shuffle
-list: "https://leetcode.com/problem-list/quicksort/"
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Quicksort.
-:::

apps/docs/content/appendix/(2-algorithms)/recursion.mdx

@@ -1,11 +0,0 @@
----
-title: "Recursion"
-list: "https://leetcode.com/problem-list/recursion/"
-icon: iteration-ccw
-sidebar:
-  badge: '3'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Recursion.
-:::

apps/docs/content/appendix/(2-algorithms)/simulation.mdx

@@ -1,11 +0,0 @@
----
-title: "Simulation"
-list: "https://leetcode.com/problem-list/simulation/"
-icon: monitor-play
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Simulation.
-:::

apps/docs/content/appendix/(2-algorithms)/sorting.mdx

@@ -1,11 +0,0 @@
----
-title: "Sorting"
-list: "https://leetcode.com/problem-list/sorting/"
-icon: arrow-down-wide-narrow
-sidebar:
-  badge: '12'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Sorting.
-:::

apps/docs/content/appendix/(2-algorithms)/tournament-sort.mdx

@@ -1,11 +0,0 @@
----
-title: "Tournament Sort"
-list: "https://leetcode.com/problem-list/tournament-sort/"
-icon: trophy
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Tournament Sort.
-:::

apps/docs/content/appendix/(3-techniques)/combinatorics.mdx

@@ -1,11 +0,0 @@
----
-title: "Combinatorics"
-list: "https://leetcode.com/problem-list/combinatorics/"
-icon: dices
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Combinatorics.
-:::

apps/docs/content/appendix/(3-techniques)/counting.mdx

@@ -1,11 +0,0 @@
----
-title: "Counting"
-list: "https://leetcode.com/problem-list/counting/"
-icon: tally-5
-sidebar:
-  badge: '3'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Counting.
-:::

apps/docs/content/appendix/(3-techniques)/design.mdx

@@ -1,11 +0,0 @@
----
-title: "Design"
-list: "https://leetcode.com/problem-list/design/"
-icon: pencil-ruler
-sidebar:
-  badge: '5'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Design.
-:::

apps/docs/content/appendix/(3-techniques)/geometry.mdx

@@ -1,11 +0,0 @@
----
-title: "Geometry"
-list: "https://leetcode.com/problem-list/geometry/"
-icon: shapes
-sidebar:
-  badge: '1'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Geometry.
-:::

apps/docs/content/appendix/(3-techniques)/math.mdx

@@ -1,11 +0,0 @@
----
-title: "Math"
-list: "https://leetcode.com/problem-list/math/"
-icon: calculator
-sidebar:
-  badge: '7'
----
-
-:::note
-This guide has not been written yet. The LeetCode list above has every problem tagged Math.
-:::

apps/docs/content/appendix/(3-techniques)/meta.ts

@@ -1,3 +0,0 @@
-import { defineMeta } from "blume";
-
-export default defineMeta({ title: "Techniques", order: 3 });

apps/docs/content/appendix/meta.ts

@@ -1,3 +0,0 @@
-import { defineMeta } from "blume";
-
-export default defineMeta({ title: "Appendix", icon: "library", order: 0, display: "page" });