docs: add segment tree image

Author: 4ndrelim

README.md

@@ -38,6 +38,7 @@ Gradle is used for development.
   - [Monotonic Queue](src/main/java/dataStructures/queue/monotonicQueue)
 - Segment Tree
 - [Stack](src/main/java/dataStructures/stack)
+- [Segment Tree](src/main/java/dataStructures/segmentTree)
 - [Trie](src/main/java/dataStructures/trie)
 
 ## Algorithms
@@ -86,6 +87,7 @@ Gradle is used for development.
     * [AVL-tree](src/main/java/dataStructures/avlTree)
     * [Trie](src/main/java/dataStructures/trie)
     * [B-Tree](src/main/java/dataStructures/bTree)
+    * [Segment Tree](src/main/java/dataStructures/segmentTree) (Not covered in CS2040s but useful!)
     * Red-Black Tree (Not covered in CS2040s but useful!)
     * Orthogonal Range Searching (**WIP**)
     * Interval Trees (**WIP**)

docs/assets/images/SegmentTree.png

@@ -5,6 +5,8 @@ Segment Trees are primarily used to solve problems that require answers to queri
 with the possibility of modifying the array elements. 
 These queries could be finding the sum, minimum, or maximum in a subarray, or similar aggregated results.
 
+![Segment Tree](../../../../../docs/assets/images/SegmentTree.png)
+
 ### Structure 
 (Note: See below for a brief description of the array-based implementation of a segment tree)