Update README.md

Author: yuelchen

README.md

@@ -5,7 +5,7 @@ This repository is a collection of Java projects for brushing up on Data Structu
 If you found this work to be helpful and would like support me, please consider getting me a ☕ ko-fi :)
 
 ## We Used Generics
-The Data Structure and Algorithm Java classes are written with Generics. 
+The custom Data Structure and Algorithm Java classes are written with Generics. 
 A Java class with Generics has a parameterized type which allows that Java class to use a different data type. 
 
 Example: The Java List class uses Generics to allow us to define a list of different Data Types. 
@@ -15,10 +15,35 @@ List<Integer> listOfIntegers = new ArrayList<>();
 ```
 
 ## Repository Overview
-### Incomplete
-#### 🎯 \[[custom-data-structure]()\]/
-#### 🎯 \[[practice-algorithms]()\]/
+### Incomplete - Use the below to implement your own solutions.
+#### 🎯 \[[custom-data-structure](https://github.com/yuelchen/java-interview-prep/tree/main/custom-data-structure)\]/
+#### 🎯 \[[practice-algorithms](https://github.com/yuelchen/java-interview-prep/tree/main/practice-algorithms)\]/
 
-### Completed
-#### 🎯 \[[custom-data-structure \[complete\]]()\]/
-#### 🎯 \[[practice-algorithms \[complete\]]()\]/
+### Completed - Use the below as reference and review. 
+#### 🎯 \[[custom-data-structure \[complete\]](https://github.com/yuelchen/java-interview-prep/tree/main/custom-data-structure%20%5Bcomplete%5D)\]/
+#### 🎯 \[[practice-algorithms \[complete\]](https://github.com/yuelchen/java-interview-prep/tree/main/practice-algorithms%20%5Bcomplete%5D)\]/
+
+## Data Structures Custom Implementations:
+- Queue 
+- Stack 
+- HashSet
+- HashMap
+- Singly Linked List
+- Doubly Linked List
+- Circular Singly Linked List
+- Circular Doubly Linked List
+- Directed Graph
+- Undirected Graph
+- Binary Search Tree
+- Binary Min Heap
+- Binary Max Heap
+
+## Algorithm Implementations:
+### Searching 
+- Linear Search
+- Binary Search
+### Sorting
+- Selection Sort
+- Insertion Sort
+- Quick Sort
+- Merge Sort