Updated 0018 - 4Sum.md ad per requested

Updated 0018 - 4Sum.md ad per requested

Author: katarianikita2003

dsa-solutions/lc-solutions/0000-0099/0018-4Sum.md

@@ -6,11 +6,7 @@ tags:
     - Arrays
     - Hashing
     - Two Pointers
-description: Given an array `nums` of `n` integers, return an array of all the unique quadruplets `[nums[a], nums[b], nums[c], nums[d]]` such that:
-
-- `0 <= a, b, c, d < n`
-- `a, b, c, and d are distinct`
-- `nums[a] + nums[b] + nums[c] + nums[d] == target`
+description: Given an array `nums` of `n` integers, return an array of all the unique quadruplets `[nums[a], nums[b], nums[c], nums[d]]`
 
 ---
 
@@ -45,9 +41,9 @@ Write a function that finds all unique quadruplets in the array which gives the
 - **Output:** `[2,2,2,2]`
 
 ## Constraints
-- `1 <= nums.length <= 200`
-- `-10^9 <= nums[i] <= 10^9`
-- `-10^9 <= target <= 10^9`
+- $1 \leq \text{nums.length} \leq 200$
+- $-10^9 \leq \text{nums}[i] \leq 10^9$
+- $-10^9 \leq \text{target} \leq 10^9$
 
 ## Approach
 1. **Sorting**: Start by sorting the array `nums`. This helps in avoiding duplicates and simplifies the two-pointer approach.