no message

Percolation/PercolationStats.java

@@ -1,8 +1,4 @@
-/* *****************************************************************************
- *  Name:              Alan Turing
- *  Coursera User ID:  123456
- *  Last modified:     1/1/2019
- **************************************************************************** */
+
 import edu.princeton.cs.algs4.StdRandom;
 
 public class PercolationStats {

Queues/src/Dequeue.java → Queues/src/Deque.java

@@ -1,11 +1,7 @@
-import javax.print.DocFlavor;
-import java.util.ArrayList;
 import java.util.Iterator;
-import java.util.Scanner;
 
-public class Dequeue<Item> implements Iterable<Item> {
-
-    public class Node<Item> {
+public class Deque<Item> implements Iterable<Item> {
+    private class Node {
         private Item item;
         private Node next;
 
@@ -27,10 +23,11 @@ public Item getItem() {
         }
     }
 
-    private Node<Item> first;
+    private Node first;
+    private int size;
 
     // construct an empty deque
-    public Dequeue() {
+    public Deque() {
         first = null;
     }
 
@@ -44,53 +41,45 @@ public boolean isEmpty() {
 
     // return the number of items on the deque
     public int size() {
-        Node<Item> tem = first;
-        if(first == null) {
-            return 0;
-        }
-        int count = 0;
-        while(true) {
-            if(tem.getNext() == null) {
-                break;
-            }
-            count++;
-            tem = tem.getNext();
-        }
-        return count;
+        return size;
     }
 
     // add the item to the front
     public void addFirst(Item item) {
         if(item == null) {
             throw new java.lang.IllegalArgumentException();
         }
-        Node<Item> tem = new Node(item);
+        Node tem = new Node(item);
         if(first == null) {
             first = tem;
+            size++;
             return;
         }
         tem.setNext(first);
         first = tem;
+        size++;
     }
 
     // add the item to the back
     public void addLast(Item item) {
         if(item == null) {
             throw new java.lang.IllegalArgumentException();
         }
-        Node<Item> tem = new Node(item);
+        Node tem = new Node(item);
         if(first == null) {
             first = tem;
+            size++;
             return;
         }
-        Node<Item> iter = first;
+        Node iter = first;
         while(true) {
             if(iter.getNext() == null) {
                 break;
             }
             iter = iter.getNext();
         }
         iter.setNext(tem);
+        size++;
     }
 
     // remove and return the item from the front
@@ -100,6 +89,7 @@ public Item removeFirst() {
         }
         Item tem = first.getItem();
         first = first.getNext();
+        size--;
         return tem;
     }
 
@@ -108,22 +98,25 @@ public Item removeLast() {
         if(first == null) {
             throw new java.util.NoSuchElementException();
         }
-        Node<Item> iter = first;
-        while(true) {
-            if(iter.getNext() == null) {
-                break;
-            }
-            iter = iter.getNext();
+        Node iter = first;
+        Node finder = first.getNext();
+        if(finder == null) {
+            Item tem = iter.getItem();
+            first = null;
+            size--;
+            return tem;
         }
-        Node<Item> finder = first;
         while(true) {
-            if(finder.getNext() == iter) {
+            if(finder.getNext() == null) {
                 break;
             }
-            finder = first.getNext();
+            iter = iter.getNext();
+            finder = finder.getNext();
         }
-        Item tem = iter.getItem();
-        finder.setNext(null);
+
+        Item tem = finder.getItem();
+        iter.setNext(null);
+        size--;
         return tem;
     }
 
@@ -134,17 +127,20 @@ public Iterator<Item> iterator() {
     }
 
     private class QueueIterator implements Iterator<Item> {
-        private Node<Item> currnet = first;
+        private Node current = first;
 
         @Override
         public boolean hasNext() {
-            return currnet != null;
+            return current != null;
         }
 
         @Override
         public Item next() {
-            Item item = currnet.getItem();
-            currnet = currnet.getNext();
+            if(hasNext() == false) {
+                throw  new java.util.NoSuchElementException();
+            }
+            Item item = current.getItem();
+            current = current.getNext();
             return item;
         }
 
@@ -157,29 +153,6 @@ public void remove() {
 
     // unit testing (required)
     public static void main(String[] args) {
-        Dequeue<Integer> app = new Dequeue<>();
-        Scanner sc = new Scanner(System.in);
-        StringBuilder builder = new StringBuilder();
-        builder.append("----DEQUEUE----\n")
-                .append("(1) add        (2) print        (3) exit\n");
-        while(true) {
-            System.out.print(builder.toString());
-
-            int menu = sc.nextInt();
-            if(menu == 1) {
-                app.addLast(sc.nextInt());
-            }
-            else if(menu == 2) {
-                for(Integer i: app) {
-                    System.out.print(i + "  ");
-                }
-                System.out.print("\n");
-            }
-            else {
-                break;
-            }
-
-        }
 
     }