From a1c1b2a0f4a291fa4afec25eba588f88d116c755 Mon Sep 17 00:00:00 2001
From: hitanshu310 <hitanshu98@gmail.com>
Date: Sun, 26 Jan 2025 21:24:16 +0530
Subject: [PATCH 1/5] Adding ArrayStack Implementation

---
 .../hithomelabs/clients/ArrayStackClient.java | 19 ++++
 .../{Main.java => LinkedArrayClient.java}     |  2 +-
 .../princeton1/module4/ArrayStack.java        | 96 +++++++++++++++++++
 3 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 clients/src/main/java/com/hithomelabs/clients/ArrayStackClient.java
 rename clients/src/main/java/com/hithomelabs/clients/{Main.java => LinkedArrayClient.java} (95%)
 create mode 100644 module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java

diff --git a/clients/src/main/java/com/hithomelabs/clients/ArrayStackClient.java b/clients/src/main/java/com/hithomelabs/clients/ArrayStackClient.java
new file mode 100644
index 0000000..53a40c1
--- /dev/null
+++ b/clients/src/main/java/com/hithomelabs/clients/ArrayStackClient.java
@@ -0,0 +1,19 @@
+package com.hithomelabs.clients;
+
+import com.hithomelabs.princeton1.module4.ArrayStack;
+import com.hithomelabs.princeton1.module4.Stack;
+
+public class ArrayStackClient {
+    public static void main(String[] args) {
+        Stack<Integer> stack = new ArrayStack<Integer>();
+        for(int i = 0; i < 21; i++){
+            stack.push(i);
+        }
+        // Using object s, as stack is generic but every java Object has implementation of toString()
+        for (Object s : stack)
+            System.out.println(s);
+        while(!stack.isEmpty()){
+            System.out.println(stack.pop());
+        }
+    }
+}
diff --git a/clients/src/main/java/com/hithomelabs/clients/Main.java b/clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java
similarity index 95%
rename from clients/src/main/java/com/hithomelabs/clients/Main.java
rename to clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java
index d8c5d68..ce51e32 100644
--- a/clients/src/main/java/com/hithomelabs/clients/Main.java
+++ b/clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java
@@ -4,7 +4,7 @@ package com.hithomelabs.clients;
 import com.hithomelabs.princeton1.module4.LinkedStack;
 import com.hithomelabs.princeton1.module4.Stack;
 
-public class Main {
+public class LinkedArrayClient {
     public static void main(String[] args) {
         Stack<String> stack = new LinkedStack<String>();
         stack.push("hello");
diff --git a/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java
new file mode 100644
index 0000000..42e0623
--- /dev/null
+++ b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java
@@ -0,0 +1,96 @@
+package com.hithomelabs.princeton1.module4;
+import java.util.Iterator;
+
+// Concrete implementation of stack using arrays
+// Creating a generic stack of type E
+public class ArrayStack<E> extends Stack<E> {
+
+    // Capacity and size are two variables, capacity determines total capacity of array, capacity defaults at 10
+    // Everytime size == capacity, capacity = 2 * capacity
+    private static final int DEFAULT_CAPACITY = 10;
+    private int capacity;
+    private int size;
+    private E[] arr;
+
+    public ArrayStack(int capacity){
+        this.capacity = capacity;
+        this.arr = (E[]) new Object[this.capacity];
+    }
+
+    // Constructor chaining, default constructor will call parametrised constructor with default initial capacity 10
+    public ArrayStack(){
+        this(DEFAULT_CAPACITY);
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return this.size == 0;
+    }
+
+    private void changeCapacity(int newCapacity){
+        E[] resizedArr = (E[]) new Object[newCapacity];
+        for (int i = 0; i < this.size; i++)
+            resizedArr[i] = this.arr[i];
+        this.arr = resizedArr;
+    }
+
+    private void incrementSize(){
+        if (this.size == this.capacity){
+            this.capacity = 2 * this.capacity;
+            changeCapacity(this.capacity);
+        }
+    }
+
+    // Push always happens at the end of the stack
+    // Say the size of the stack is 1, new element gets inserted  at 1
+    @Override
+    public void push(E element) {
+        // Lazy approach, we assume size to always be lesser than capacity
+        this.incrementSize();
+        this.arr[this.size++] = element;
+    }
+
+    @Override
+    public E pop() {
+        if (isEmpty())
+            return null;
+        else{
+            E e = this.arr[--this.size];
+            this.arr[this.size] = null;
+            this.checkResize();
+            return e;
+        }
+    }
+
+    private void checkResize() {
+        if (this.size < this.capacity / 4 && this.capacity > 10){
+            this.capacity = this.capacity / 2;
+            changeCapacity(this.capacity);
+        }
+    }
+
+    @Override
+    public int size() {
+        return this.size;
+    }
+
+    @Override
+    public Iterator<E> iterator() {
+        return new Iterator<E>() {
+
+            int current = 0;
+
+            @Override
+            public boolean hasNext() {
+                return current != size;
+            }
+
+            @Override
+            public E next() {
+                E element = arr[current];
+                current = current + 1;
+                return element;
+            }
+        };
+    }
+}
-- 
2.45.2


From 09ec2b8bb0ca915fa821894dae455db36d790a89 Mon Sep 17 00:00:00 2001
From: hitanshu310 <hitanshu98@gmail.com>
Date: Mon, 27 Jan 2025 00:05:30 +0530
Subject: [PATCH 2/5] Checking in Queue implementation of Array

---
 .idea/vcs.xml                                 |   6 +
 .../hithomelabs/clients/ArrayQueueClient.java |  22 ++++
 .../princeton1/module4/ArrayQueue.java        | 103 ++++++++++++++++++
 .../princeton1/module4/ArrayStack.java        |  36 +++---
 .../hithomelabs/princeton1/module4/Queue.java |  10 ++
 5 files changed, 160 insertions(+), 17 deletions(-)
 create mode 100644 .idea/vcs.xml
 create mode 100644 clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
 create mode 100644 module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayQueue.java
 create mode 100644 module4/src/main/java/com/hithomelabs/princeton1/module4/Queue.java

diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java b/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
new file mode 100644
index 0000000..dca3c9f
--- /dev/null
+++ b/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
@@ -0,0 +1,22 @@
+package com.hithomelabs.clients;
+
+import com.hithomelabs.princeton1.module4.ArrayQueue;
+import com.hithomelabs.princeton1.module4.ArrayStack;
+import com.hithomelabs.princeton1.module4.Queue;
+import com.hithomelabs.princeton1.module4.Stack;
+
+public class ArrayQueueClient {
+    public static void main(String[] args) {
+        Queue<Integer> queue = new ArrayQueue<Integer>();
+        for(int i = 0; i < 21; i++){
+            queue.enqueue(i);
+        }
+        for(int i = 0; i < 13; i++){
+            System.out.println(queue.dequeue());
+        }
+
+        // Using object s, as stack is generic but every java Object has implementation of toString()
+        for (Object s : queue)
+            System.out.println(s);
+        }
+    }
diff --git a/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayQueue.java b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayQueue.java
new file mode 100644
index 0000000..4e8988e
--- /dev/null
+++ b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayQueue.java
@@ -0,0 +1,103 @@
+package com.hithomelabs.princeton1.module4;
+
+import javax.annotation.Nonnull;
+import java.util.Iterator;
+
+public class ArrayQueue<E> extends Queue<E>{
+
+    // insertion from tail, removal from head
+    public static final int DEFAULT_CAPACITY = 10;
+    private int capacity;
+    private int tail;
+    private int head;
+    private int size;
+    private E[] arr;
+
+    public ArrayQueue(){
+        this(DEFAULT_CAPACITY);
+    }
+
+    public ArrayQueue(int capacity){
+        this.capacity = capacity;
+        arr = (E[]) new Object[this.capacity];
+        size = 0;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    @Override
+    public E dequeue() {
+        if(isEmpty())
+            return null;
+        else{
+            E element = arr[head];
+            // Garbage collection
+            arr[head] = null;
+            head = (head+1)%capacity;
+            size = size - 1;
+            if(capacity >= 40 && size < capacity/4){
+                capacity = capacity/2;
+                resize(capacity, capacity*2);
+            }
+            return element;
+        }
+    }
+
+    @Override
+    public void enqueue(E element) {
+        // We plan capacity expansion if needed
+        if (size == capacity){
+            capacity = capacity * 2;
+            resize(capacity, capacity/2);
+        }
+        arr[tail] = element;
+        tail = (tail + 1) % capacity;
+        ++size;
+    }
+
+    // When resize takes place always the original array is full, so copy the complete array as is
+    private void resize(int capacity, int oldCapacity) {
+        E[] resizedArr = (E[]) new Object[capacity];
+        for(int i = 0; i < size; i++) {
+            resizedArr[i] = arr[head];
+            // halving because capacity has now doubled
+            arr[head] = null;
+            head = (head + 1) % oldCapacity;
+        }
+        arr = resizedArr;
+        // When resizing takes place, we bring the head to 0 and the tail to size
+        // tail is where new inserts will be made and head will be where elements will be removed
+        tail = size;
+        head = 0;
+
+    }
+
+    @Override
+    public int size() {
+        return size;
+    }
+
+    @Override
+    @Nonnull
+    public Iterator<E> iterator() {
+        return new Iterator<E>() {
+            int counter = size;
+            int pointer = head;
+            @Override
+            public boolean hasNext() {
+                return counter != 0;
+            }
+
+            @Override
+            public E next() {
+                E element = arr[pointer];
+                pointer = (pointer + 1)% capacity;
+                --counter;
+                return element;
+            }
+        };
+    }
+}
diff --git a/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java
index 42e0623..0ae2eb6 100644
--- a/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java
+++ b/module4/src/main/java/com/hithomelabs/princeton1/module4/ArrayStack.java
@@ -1,4 +1,5 @@
 package com.hithomelabs.princeton1.module4;
+import javax.annotation.Nonnull;
 import java.util.Iterator;
 
 // Concrete implementation of stack using arrays
@@ -14,7 +15,7 @@ public class ArrayStack<E> extends Stack<E> {
 
     public ArrayStack(int capacity){
         this.capacity = capacity;
-        this.arr = (E[]) new Object[this.capacity];
+        arr = (E[]) new Object[this.capacity];
     }
 
     // Constructor chaining, default constructor will call parametrised constructor with default initial capacity 10
@@ -24,20 +25,20 @@ public class ArrayStack<E> extends Stack<E> {
 
     @Override
     public boolean isEmpty() {
-        return this.size == 0;
+        return size == 0;
     }
 
     private void changeCapacity(int newCapacity){
         E[] resizedArr = (E[]) new Object[newCapacity];
-        for (int i = 0; i < this.size; i++)
-            resizedArr[i] = this.arr[i];
-        this.arr = resizedArr;
+        for (int i = 0; i < size; i++)
+            resizedArr[i] = arr[i];
+        arr = resizedArr;
     }
 
     private void incrementSize(){
-        if (this.size == this.capacity){
-            this.capacity = 2 * this.capacity;
-            changeCapacity(this.capacity);
+        if (size == capacity){
+            capacity = 2 * capacity;
+            changeCapacity(capacity);
         }
     }
 
@@ -46,8 +47,8 @@ public class ArrayStack<E> extends Stack<E> {
     @Override
     public void push(E element) {
         // Lazy approach, we assume size to always be lesser than capacity
-        this.incrementSize();
-        this.arr[this.size++] = element;
+        incrementSize();
+        arr[size++] = element;
     }
 
     @Override
@@ -55,26 +56,27 @@ public class ArrayStack<E> extends Stack<E> {
         if (isEmpty())
             return null;
         else{
-            E e = this.arr[--this.size];
-            this.arr[this.size] = null;
-            this.checkResize();
+            E e = arr[--size];
+            arr[size] = null;
+            checkResize();
             return e;
         }
     }
 
     private void checkResize() {
-        if (this.size < this.capacity / 4 && this.capacity > 10){
-            this.capacity = this.capacity / 2;
-            changeCapacity(this.capacity);
+        if (size < capacity / 4 && capacity >= 40){
+            capacity = capacity / 2;
+            changeCapacity(capacity);
         }
     }
 
     @Override
     public int size() {
-        return this.size;
+        return size;
     }
 
     @Override
+    @Nonnull
     public Iterator<E> iterator() {
         return new Iterator<E>() {
 
diff --git a/module4/src/main/java/com/hithomelabs/princeton1/module4/Queue.java b/module4/src/main/java/com/hithomelabs/princeton1/module4/Queue.java
new file mode 100644
index 0000000..6c4999d
--- /dev/null
+++ b/module4/src/main/java/com/hithomelabs/princeton1/module4/Queue.java
@@ -0,0 +1,10 @@
+package com.hithomelabs.princeton1.module4;
+
+public abstract class Queue<E> implements Iterable<E> {
+
+    public abstract boolean isEmpty();
+    public abstract E dequeue();
+    public abstract void enqueue(E element);
+    public abstract int size();
+}
+
-- 
2.45.2


From 6774300a8a81d2366775b1fa73cbb17edad1c5db Mon Sep 17 00:00:00 2001
From: hitanshu310 <hitanshu98@gmail.com>
Date: Mon, 27 Jan 2025 01:29:14 +0530
Subject: [PATCH 3/5] Adding Queue linked list client

---
 .../hithomelabs/clients/ArrayQueueClient.java |  2 -
 .../clients/LinkedQueueClient.java            | 20 +++++
 ...rrayClient.java => LinkedStackClient.java} |  2 +-
 .../princeton1/module4/LinkedQueue.java       | 74 +++++++++++++++++++
 4 files changed, 95 insertions(+), 3 deletions(-)
 create mode 100644 clients/src/main/java/com/hithomelabs/clients/LinkedQueueClient.java
 rename clients/src/main/java/com/hithomelabs/clients/{LinkedArrayClient.java => LinkedStackClient.java} (95%)
 create mode 100644 module4/src/main/java/com/hithomelabs/princeton1/module4/LinkedQueue.java

diff --git a/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java b/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
index dca3c9f..7022367 100644
--- a/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
+++ b/clients/src/main/java/com/hithomelabs/clients/ArrayQueueClient.java
@@ -1,9 +1,7 @@
 package com.hithomelabs.clients;
 
 import com.hithomelabs.princeton1.module4.ArrayQueue;
-import com.hithomelabs.princeton1.module4.ArrayStack;
 import com.hithomelabs.princeton1.module4.Queue;
-import com.hithomelabs.princeton1.module4.Stack;
 
 public class ArrayQueueClient {
     public static void main(String[] args) {
diff --git a/clients/src/main/java/com/hithomelabs/clients/LinkedQueueClient.java b/clients/src/main/java/com/hithomelabs/clients/LinkedQueueClient.java
new file mode 100644
index 0000000..008742c
--- /dev/null
+++ b/clients/src/main/java/com/hithomelabs/clients/LinkedQueueClient.java
@@ -0,0 +1,20 @@
+package com.hithomelabs.clients;
+
+import com.hithomelabs.princeton1.module4.LinkedQueue;
+import com.hithomelabs.princeton1.module4.Queue;
+
+public class LinkedQueueClient {
+    public static void main(String[] args) {
+        Queue<Integer> queue = new LinkedQueue<Integer>();
+        for(int i = 0; i < 21; i++){
+            queue.enqueue(i);
+        }
+        for(int i = 0; i < 13; i++){
+            System.out.println(queue.dequeue());
+        }
+
+        // Using object s, as stack is generic but every java Object has implementation of toString()
+        for (Object s : queue)
+            System.out.println(s);
+        }
+    }
diff --git a/clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java b/clients/src/main/java/com/hithomelabs/clients/LinkedStackClient.java
similarity index 95%
rename from clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java
rename to clients/src/main/java/com/hithomelabs/clients/LinkedStackClient.java
index ce51e32..33cc4e9 100644
--- a/clients/src/main/java/com/hithomelabs/clients/LinkedArrayClient.java
+++ b/clients/src/main/java/com/hithomelabs/clients/LinkedStackClient.java
@@ -4,7 +4,7 @@ package com.hithomelabs.clients;
 import com.hithomelabs.princeton1.module4.LinkedStack;
 import com.hithomelabs.princeton1.module4.Stack;
 
-public class LinkedArrayClient {
+public class LinkedStackClient {
     public static void main(String[] args) {
         Stack<String> stack = new LinkedStack<String>();
         stack.push("hello");
diff --git a/module4/src/main/java/com/hithomelabs/princeton1/module4/LinkedQueue.java b/module4/src/main/java/com/hithomelabs/princeton1/module4/LinkedQueue.java
new file mode 100644
index 0000000..ec37bbe
--- /dev/null
+++ b/module4/src/main/java/com/hithomelabs/princeton1/module4/LinkedQueue.java
@@ -0,0 +1,74 @@
+package com.hithomelabs.princeton1.module4;
+
+import javax.annotation.Nonnull;
+import java.util.Iterator;
+
+public class LinkedQueue<E> extends Queue<E>{
+
+    Node head;
+    Node tail;
+    int size;
+
+    private class Node{
+        E value;
+        Node next;
+
+        Node(E value){
+            this.value = value;
+        }
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return size==0;
+    }
+
+    @Override
+    public E dequeue() {
+        if(isEmpty())
+            return null;
+        E element = head.value;
+        // Only a single element is present
+        if (head == tail){
+            tail = null;
+        }
+        head = head.next;
+        --size;
+        return element;
+    }
+
+    @Override
+    public void enqueue(E element) {
+        Node newNode = new Node(element);
+        if(isEmpty())
+            head = newNode;
+        else
+            tail.next = newNode;
+        tail = newNode;
+        ++size;
+    }
+
+    @Override
+    public int size() {
+        return size;
+    }
+
+    @Override
+    @Nonnull
+    public Iterator<E> iterator() {
+        return new Iterator<E>() {
+            Node current = head;
+            @Override
+            public boolean hasNext() {
+                return current != tail;
+            }
+
+            @Override
+            public E next() {
+                E element = current.value;
+                current = current.next;
+                return element;
+            }
+        };
+    }
+}
-- 
2.45.2


From 6747e07be4083685df6eca17d1e4af0693e13e6a Mon Sep 17 00:00:00 2001
From: hitanshu310 <hitanshu98@gmail.com>
Date: Mon, 27 Jan 2025 01:55:12 +0530
Subject: [PATCH 4/5] Initializing gradle build workflows

---
 .gitea/workflows/gradle_build.yml | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 .gitea/workflows/gradle_build.yml

diff --git a/.gitea/workflows/gradle_build.yml b/.gitea/workflows/gradle_build.yml
new file mode 100644
index 0000000..e8d515a
--- /dev/null
+++ b/.gitea/workflows/gradle_build.yml
@@ -0,0 +1,24 @@
+name: sample gradle build and test
+run-name: Build started by $ {{gitea.actor }}
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - name: JDK setup
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'zulu'
+          java-version: '21'
+      - name: Validate Gradle Wrapper
+        uses: gradle/actions/wrapper-validation@v3
+      - name: Gradle build
+        run: ./greadlew build -i
+
-- 
2.45.2


From 74991617250ffe42fba2ee5ffc21434eafe0d53e Mon Sep 17 00:00:00 2001
From: hitanshu310 <hitanshu98@gmail.com>
Date: Mon, 27 Jan 2025 02:10:44 +0530
Subject: [PATCH 5/5] Fixing typo to avoid gradle build failure

---
 .gitea/workflows/gradle_build.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitea/workflows/gradle_build.yml b/.gitea/workflows/gradle_build.yml
index e8d515a..f135547 100644
--- a/.gitea/workflows/gradle_build.yml
+++ b/.gitea/workflows/gradle_build.yml
@@ -20,5 +20,5 @@ jobs:
       - name: Validate Gradle Wrapper
         uses: gradle/actions/wrapper-validation@v3
       - name: Gradle build
-        run: ./greadlew build -i
+        run: ./gradlew build -i
 
-- 
2.45.2