feat: refactored docs structure

apps/docs/content/(01-linear-structures)/hash-table/(problems)/242_valid-anagram.mdx

@@ -1,66 +0,0 @@
----
-title: '242. Valid Anagram'
-description: Given two strings s and t, return true if t is an anagram of s, and false otherwise
-icon: dot
-topics:
-  - { name: "Hash Table", slug: "hash-table" }
-  - { name: "String", slug: "string" }
-  - { name: "Sorting", slug: "sorting" }
-video: "9UtInBqnCgA"
-issue: "https://github.com/prdlk/leetcode/issues/28"
-sidebar:
-  label: 'Valid Anagram'
-  badge: 'Easy'
----
-
-::::warning
-What if the inputs contain Unicode characters? How would you adapt your solution to such a case?
-::::
-
-### Example 1:
-- Input: `s = "anagram", t = "nagaram"`
-- Output: `true`
-
-### Example 2:
-- Input: `s = "rat", t = "car"`
-- Output: `false`
-
-### Constraints:
-
-- `1 <= s.length, t.length <= 5 * 10^4`
-- `s` and `t` consist of lowercase English letters.
-
-## Approach
-
-```mermaid
-flowchart TD
-  S(["isAnagram(s, t)"]) --> I["freq: count every char of s"]
-  I --> L{"more char c in t?"}
-  L -- no --> E(["return true"])
-  L -- yes --> Q{"freq[c] missing or 0?"}
-  Q -- yes --> R(["return false — t has a char s cannot cover"])
-  Q -- no --> D["freq[c] -= 1"]
-  D --> L
-```
-
-## Solution
-
-```js
-/**
- * @param {string} s
- * @param {string} t
- * @return {boolean}
- */
-var isAnagram = function(s, t) {
-  let freq = {};
-  for (let c of s) freq[c] = (freq[c] || 0) + 1;
-  
-  for (let c of t) {
-    if(!freq[c] || freq[c] === 0){
-      return false;
-    }
-    freq[c] = freq[c] - 1;
-  }
-  return true;
-};
-```