Stack Updates

Stack Updates

Author: careermonk

bin/chapter3linkedlists/LinkedList.class

@@ -93,6 +93,20 @@ public synchronized ListNode removeFromBegin() {
 		}
 		return node;
 	}
+	
+	// Remove and return the node at the end of the list 
+	public synchronized ListNode getLast() {
+		if (head == null) 
+			return null;
+		if (head.getNext() == null) {
+			return head;
+		}
+		ListNode p = head.getNext();
+		while(p.getNext() != null) { 
+			p = p.getNext();
+		}
+		return p;
+	}
 
 	// Remove and return the node at the end of the list 
 	public synchronized ListNode removeFromEnd() {
@@ -201,6 +215,11 @@ public int getPosition(int data) {
 		return Integer.MIN_VALUE;
 	}
 
+	// Size of the list.
+	public boolean isEmpty(){
+		return length==0;
+	}
+	
 	// Remove everything from the list.
 	public void clearList(){
 		head = null;

bin/chapter4stacks/LinkedStack.class

@@ -16,7 +16,7 @@
 import chapter3linkedlists.*;
 import java.util.EmptyStackException;
 
-public class LinkedStack<T>{
+public class LinkedStack{
 	private int length;  		// indicates the size of the linked list
 	private ListNode top; 
 

bin/chapter4stacks/StackForStackSets.class

@@ -0,0 +1,57 @@
+/*Copyright (c) Dec 22, 2014 CareerMonk Publications and others.
+ * E-Mail           	: info@careermonk.com 
+ * Creation Date    	: 2015-01-10 06:15:46 
+ * Last modification	: 2006-05-31 
+               by		: Narasimha Karumanchi 
+ * File Name			: StackForStackSets.java
+ * Book Title			: Data Structures And Algorithms Made In Java
+ * Warranty         	: This software is provided "as is" without any 
+ * 							warranty; without even the implied warranty of 
+ * 							merchantability or fitness for a particular purpose. 
+ * 
+ */
+
+
+package chapter4stacks;
+
+class StackForStackSets {
+    
+    private int top = -1;   
+    private int[] arr;
+    // Maximum size of stack
+    private int capacity;
+     
+    StackForStackSets(int capacity){
+        this.capacity = capacity;
+        arr = new int[capacity];
+    }
+     
+    public void push(int v){
+        arr[++top] = v;
+    }
+     
+    public int pop(){
+         
+        return arr[top--];
+    }
+    
+    // if the stack is at capacity
+    public Boolean isAtCapacity(){
+        return capacity == top + 1;
+    }
+    
+    //return the size of the stack
+    public int size(){
+        return top+1;
+    }
+     
+    public String toString(){
+        String s = "";
+        int index = top;
+        while(index >= 0){
+            s += "[" + arr[index--] + "]"+ " --> ";
+        }
+        return s;
+         
+    }
+}

bin/chapter4stacks/StackSets.class

@@ -0,0 +1,103 @@
+/*Copyright (c) Dec 22, 2014 CareerMonk Publications and others.
+ * E-Mail           	: info@careermonk.com 
+ * Creation Date    	: 2015-01-10 06:15:46 
+ * Last modification	: 2006-05-31 
+               by		: Narasimha Karumanchi 
+ * File Name			: StackSets.java
+ * Book Title			: Data Structures And Algorithms Made In Java
+ * Warranty         	: This software is provided "as is" without any 
+ * 							warranty; without even the implied warranty of 
+ * 							merchantability or fitness for a particular purpose. 
+ * 
+ */
+
+
+package chapter4stacks;
+
+import java.util.ArrayList;
+
+public class StackSets{
+	// Number of elements for each stack
+    private int threshold;
+    private ArrayList<StackForStackSets> listOfStacks = new  ArrayList<StackForStackSets>();
+     
+    StackSets(int threshold) {
+        this.threshold = threshold;        
+    }
+    //get the last stack
+    public StackForStackSets getLastStack(){
+        int size = listOfStacks.size();
+        if(size <= 0) 
+        	return null;
+        else return listOfStacks.get(size - 1);
+    }
+     
+    //get the nth stack
+    public StackForStackSets getNthStack(int n){
+    	System.out.println(n);
+        int size = listOfStacks.size();
+        if(size <= 0) 
+        	return null;
+        else return listOfStacks.get(n - 1);
+    }
+     
+    //push value
+    public void push(int value){
+    	StackForStackSets lastStack = this.getLastStack();
+         
+        if(lastStack == null){
+            lastStack = new StackForStackSets(threshold);
+            lastStack.push(value);
+            listOfStacks.add(lastStack);
+        }else {
+            if( !lastStack.isAtCapacity())
+                lastStack.push(value);
+            else {
+            	StackForStackSets newLastStack = new StackForStackSets(threshold);
+                newLastStack.push(value);
+                listOfStacks.add(newLastStack);
+            }
+        }    
+    }
+    // the pop 
+    public int pop(){
+    	StackForStackSets lastStack = this.getLastStack();
+        int v = lastStack.pop();
+        if(lastStack.size() == 0) listOfStacks.remove(listOfStacks.size() -  1);
+        return v;
+    }
+     
+     
+    //pop from the nth stack
+    public int pop(int nth){
+    	StackForStackSets nthStack = this.getNthStack(nth);
+         int v = nthStack.pop();
+         if(nthStack.size() == 0) listOfStacks.remove(listOfStacks.size() -  1);
+         return v;   
+         
+    }
+     
+    public String toString(){
+        String s = "";
+        for(int i = 0; i < listOfStacks.size(); i++){
+        	StackForStackSets stack = listOfStacks.get(i);
+            s = "Stack "+ i + ": " + stack.toString() +  s;
+        }
+         
+        return s;
+    }
+     
+     
+    public static void main(String[] args){
+    	StackSets stacks = new StackSets(3);
+        stacks.push(10); stacks.push(9); stacks.push(8);
+        stacks.push(7); stacks.push(6); stacks.push(5);
+        stacks.push(4); stacks.push(3); stacks.push(2);
+
+        System.out.println("Popping " + stacks.pop(2));
+        System.out.println("Popping from stack 1" + stacks.pop(1));
+        System.out.println("Popping " + stacks.pop(3));
+        System.out.println("Popping " + stacks.pop(2));
+        System.out.println("the stack is: " + stacks);
+    }
+}