Pila con Linked List

src/main/java/com/utp/clsEstructuraDatos/Estructuras/linked_list/LinkedList.java

@@ -70,6 +70,21 @@ public Optional<T> remove_last() {
         return element;
     }
 
+    public Optional<T> get(int idx) {
+        if (idx < 0 || idx >= len) {
+            return Optional.empty();
+        }
+        Optional<Node<T>> child = this.child;
+        for (int i = 0; i < idx; i++) {
+            child = child.get().nextNode();
+        }
+        return Optional.of(child.get().value);
+    }
+
+    public Optional<T> peek_first() {
+        return get(0);
+    }
+
     public int size() {
         return len;
     }

src/main/java/com/utp/clsEstructuraDatos/Estructuras/pila/IStack.java

@@ -0,0 +1,23 @@
+package com.utp.clsEstructuraDatos.Estructuras.pila;
+
+public interface IStack<T> {
+    default boolean isEmpty() {
+        return (len() == 0);
+    }
+
+    default boolean isFull() {
+        return len() == capacity();
+    }
+
+    void push(T elemento);
+
+    T pop();
+
+    T peek_top();
+
+    int len();
+
+    void clear();
+
+    int capacity();
+}

src/main/java/com/utp/clsEstructuraDatos/Estructuras/pila/LEPila.java

@@ -0,0 +1,60 @@
+package com.utp.clsEstructuraDatos.Estructuras.pila;
+
+import com.utp.clsEstructuraDatos.Estructuras.linked_list.LinkedList;
+
+public class LEPila<T> implements IStack<T> {
+    int len = 0;
+    LinkedList<T> inner = new LinkedList<T>();
+
+    @Override
+    public void push(T elemento) {
+        len += 1;
+        inner.insert_first(elemento);
+    }
+
+    @Override
+    public T pop() {
+        if (isEmpty()) {
+            return null;
+        }
+        var e = inner.remove_first();
+        len -= 1;
+        if (e.isPresent()) {
+            return e.get();
+        }
+        return null;
+    }
+
+    @Override
+    public T peek_top() {
+        var e = inner.get(0);
+        if (e.isPresent()) {
+            return e.get();
+        }
+        return null;
+    }
+
+    @Override
+    public int len() {
+        return this.len;
+    }
+
+    @Override
+    public void clear() {
+        inner.clear();
+    }
+
+    @Override
+    public int capacity() {
+        return -1;
+    }
+
+    @Override
+    /**
+     * Linked List has no capacity constraint
+     */
+    public boolean isFull() {
+        return false;
+    }
+
+}

src/main/java/com/utp/clsEstructuraDatos/Estructuras/Pila.java → src/main/java/com/utp/clsEstructuraDatos/Estructuras/pila/Pila.java

@@ -1,4 +1,4 @@
-package com.utp.clsEstructuraDatos.Estructuras;
+package com.utp.clsEstructuraDatos.Estructuras.pila;
 
 import java.util.ArrayList;
 

src/main/java/com/utp/clsEstructuraDatos/laboratorio_1/Main.java

@@ -4,13 +4,14 @@
 import javax.swing.JFrame;
 import javax.swing.JOptionPane;
 
+import com.utp.clsEstructuraDatos.Estructuras.pila.Pila;
+
 import java.awt.Font;
 import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.TextArea;
 import java.util.ArrayList;
 
-import com.utp.clsEstructuraDatos.Estructuras.Pila;
 public class Main {
     public static void main(String[] args) {
         App app = new App();
@@ -32,7 +33,7 @@ void start() {
         frame.setLayout(new GridBagLayout());
         add_button_commands(frame);
         GridBagConstraints c = new GridBagConstraints();
-        
+
         // Representación en vivo de la Pila
         c.gridy = 2;
         c.gridwidth = 8;