From d60f836861fb1d1237935a9c342ef492d0df8cc4 Mon Sep 17 00:00:00 2001
From: Ojas Saxena <43749506+ojasiiitd@users.noreply.github.com>
Date: Mon, 4 Mar 2019 15:05:15 +0530
Subject: [PATCH 1/2] Updated StackOfLinkedList.java

I made the code shorter and less prone to mistakes by removing the "size" variable altogether from the LinkedList class. I found that after each push/pop operation, changing the value of size did make the code more efficient, but made it more prone to mistakes. So, for empty stack, a simple "head == null" was enough, which has been incorporated.
---
 DataStructures/Stacks/StackOfLinkedList.java | 37 +++++++++++---------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/DataStructures/Stacks/StackOfLinkedList.java b/DataStructures/Stacks/StackOfLinkedList.java
index 35052457fe1c..7b744bcb85af 100644
--- a/DataStructures/Stacks/StackOfLinkedList.java
+++ b/DataStructures/Stacks/StackOfLinkedList.java
@@ -25,9 +25,7 @@ public static void main(String[] args) {
         stack.pop();
 
         System.out.println("Top element of stack currently is: " + stack.peek());
-
     }
-
 }
 
 // A node class
@@ -51,11 +49,10 @@ public Node(int data) {
 class LinkedListStack {
 
     Node head = null;
-    int size = 0;
 
     public void push(int x) {
         Node n = new Node(x);
-        if (getSize() == 0) {
+        if (head == null) {
             head = n;
         }
         else {
@@ -63,47 +60,55 @@ public void push(int x) {
             n.next = temp;
             head = n;
         }
-        size++;
     }
 
     public void pop() {
-        if (getSize() == 0) {
+        if (head == null) {
             System.out.println("Empty stack. Nothing to pop");
         }
 
         Node temp = head;
         head = head.next;
-        size--;
-
         System.out.println("Popped element is: " + temp.data);
     }
 
     public int peek() {
-      if (getSize() == 0) {
+      if (head == null) {
         return -1;
       }
-
       return head.data;
     }
 
     public void printStack() {
-
         Node temp = head;
         System.out.println("Stack is printed as below: ");
         while (temp != null) {
-            System.out.println(temp.data + " ");
+            if(temp.next == null) {
+                System.out.print(temp.data);
+            }
+            else {
+                System.out.print(temp.data + " -> ");
+            }
             temp = temp.next;
         }
         System.out.println();
-
     }
 
     public boolean isEmpty() {
-        return getSize() == 0;
+        return head == null;
     }
 
     public int getSize() {
-        return size;
+        if(head == null)
+            return 0;
+        else {
+            int size = 1;
+            Node temp = head;
+            while(temp.next != null) {
+                temp = temp.next;
+                size++;
+            }
+            return size;
+        }
     }
-
 }

From 2ea534000bafe95a5c03dd6248aeda1d1ff151a7 Mon Sep 17 00:00:00 2001
From: yanglbme <contact@yanglibin.info>
Date: Tue, 5 Mar 2019 10:18:20 +0800
Subject: [PATCH 2/2] Update StackOfLinkedList.java

---
 DataStructures/Stacks/StackOfLinkedList.java | 24 ++++++++------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/DataStructures/Stacks/StackOfLinkedList.java b/DataStructures/Stacks/StackOfLinkedList.java
index 7b744bcb85af..d9f737040271 100644
--- a/DataStructures/Stacks/StackOfLinkedList.java
+++ b/DataStructures/Stacks/StackOfLinkedList.java
@@ -1,7 +1,5 @@
 /**
- *
  * @author Varun Upadhyay (https://github.com/varunu28)
- *
  */
 
 // An implementation of a Stack using a Linked List
@@ -42,7 +40,7 @@ public Node(int data) {
 
 /**
  * A class which implements a stack using a linked list
- *
+ * <p>
  * Contains all the stack methods : push, pop, printStack, isEmpty
  **/
 
@@ -54,8 +52,7 @@ public void push(int x) {
         Node n = new Node(x);
         if (head == null) {
             head = n;
-        }
-        else {
+        } else {
             Node temp = head;
             n.next = temp;
             head = n;
@@ -73,20 +70,19 @@ public void pop() {
     }
 
     public int peek() {
-      if (head == null) {
-        return -1;
-      }
-      return head.data;
+        if (head == null) {
+            return -1;
+        }
+        return head.data;
     }
 
     public void printStack() {
         Node temp = head;
         System.out.println("Stack is printed as below: ");
         while (temp != null) {
-            if(temp.next == null) {
+            if (temp.next == null) {
                 System.out.print(temp.data);
-            }
-            else {
+            } else {
                 System.out.print(temp.data + " -> ");
             }
             temp = temp.next;
@@ -99,12 +95,12 @@ public boolean isEmpty() {
     }
 
     public int getSize() {
-        if(head == null)
+        if (head == null)
             return 0;
         else {
             int size = 1;
             Node temp = head;
-            while(temp.next != null) {
+            while (temp.next != null) {
                 temp = temp.next;
                 size++;
             }