补数据结构作业

group24/315863321/src/main/java/com/johnChnia/coderising2017/array/ArrayUtil.java

@@ -1,6 +1,6 @@
 package com.johnChnia.coderising2017.array;
 
-import com.johnChnia.coding2017.basic.Queue;
+import com.johnChnia.coding2017.basic.queue.Queue;
 import com.johnChnia.coding2017.basic.ArrayList;
 
 

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/ArrayList.java

@@ -1,11 +1,13 @@
 package com.johnChnia.coding2017.basic;
 
 import java.util.Arrays;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
 
 /**
  * Created by john on 2017/3/8.
  *
- * @// TODO: 2017/4/1  实现Iterator 接口
+ * @// TODO: 学会多线程后，实现Iterator 的 remove 方法
  */
 
 public class ArrayList<E> implements List<E> {
@@ -138,8 +140,32 @@ public int size() {
         return size;
     }
 
+    @Override
+    public Iterator<E> iterator() {
+        return new Itr();
+    }
 
-    /**
+
+    private class Itr implements Iterator<E> {
+        int cursor = 0;
+        @Override
+        public boolean hasNext() {
+            return cursor != size;
+        }
+
+        @Override
+        public E next() {
+            int i = cursor;
+            if (i >= size) {
+                throw new NoSuchElementException();
+            }
+            Object[] elementData = ArrayList.this.elementData;
+            cursor = i + 1;
+            return (E) elementData[i];
+        }
+    }
+
+        /**
      * Increases the capacity to ensure that it can hold at least the
      * number of elements specified by the double length of list.
      */
@@ -148,6 +174,25 @@ private void grow() {
                 2 * elementData.length);
     }
 
+    public boolean contains(Object o) {
+        Itr itr = new Itr();
+        if (o == null) {
+            while (itr.hasNext()) {
+                if (itr.next() == null) {
+                    return true;
+                }
+            }
+
+        } else {
+            while (itr.hasNext()) {
+                if (itr.next().equals(o)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     public String toString() {
         StringBuilder stringBuilder = new StringBuilder();
         stringBuilder.append("[");

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/BinarySearchTree.java

@@ -1,5 +1,7 @@
 package com.johnChnia.coding2017.basic;
 
+import com.johnChnia.coding2017.basic.queue.Queue;
+
 /**
  * Created by john on 2017/3/13.
  */

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/List.java

@@ -1,16 +1,23 @@
 package com.johnChnia.coding2017.basic;
 
+import java.util.Iterator;
+
 /**
  * Created by john on 2017/3/12.
  */
-public interface List<E> {
-    public void add(E o);
+public interface List<E> extends Iterable<E>{
+    void add(E o);
+
+    void add(int index, E o);
+
+    E get(int index);
+
+    E remove(int index);
 
-    public void add(int index, E o);
+    int size();
 
-    public E get(int index);
+    Iterator<E> iterator();
 
-    public E remove(int index);
+    boolean contains(Object o);
 
-    public int size();
 }

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/linklist/LinkedList.java

@@ -2,12 +2,13 @@
 
 import com.johnChnia.coding2017.basic.List;
 
+import java.util.Iterator;
 import java.util.NoSuchElementException;
 
 /**
  * Created by john on 2017/3/9.
  *
- * @// TODO: 2017/4/1 支持Iterator
+ * @// TODO: 学会多线程后，实现Iterator 的 remove 方法
  */
 
 public class LinkedList<E> implements List<E> {
@@ -223,6 +224,40 @@ public int size() {
         return size;
     }
 
+    @Override
+    public Iterator<E> iterator() {
+        return new Itr();
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        return false;
+    }
+
+    private class Itr implements Iterator<E> {
+        /**
+         * Index of element to be returned by subsequent call to next.
+         */
+        int cursor = 0;
+
+
+        @Override
+        public boolean hasNext() {
+            return cursor != size();
+        }
+
+        @Override
+        public E next() {
+            int i = cursor;
+            if (i >= size) {
+                throw new NoSuchElementException();
+            }
+            E next = get(i);
+            cursor = i + 1;
+            return next;
+        }
+    }
+
     private void checkElementIndex(int index) {
         if (!isElementIndex(index)) {
             throw new IndexOutOfBoundsException(outOfBoundsMsg(index));

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/queue/CircleQueue.java

@@ -0,0 +1,104 @@
+package com.johnChnia.coding2017.basic.queue;
+
+/**
+ * Created by john on 2017/5/6.
+ *
+ * NOTE:循环队列下一个为(i+1)%N，上一个为(i+N-1)%N
+ */
+public class CircleQueue {
+    private int rear = -1;
+    private int front = -1;
+    private Object[] array;
+    private static final int DEFAULTCAPACITY = 10;
+
+
+    /**
+     * 构造一个空的循环队列
+     */
+    public CircleQueue() {
+        array = new Object[DEFAULTCAPACITY];
+    }
+
+    /**
+     * 根据传进来的容量构造循环队列
+     *
+     * @param capacity 队列容量
+     */
+    public CircleQueue(int capacity) {
+        array = new Object[capacity];
+    }
+
+    /**
+     * 循环队列长度
+     *
+     * @return 队列长度
+     */
+    public int size() {
+        return array.length;
+    }
+
+    /**
+     * 判断队列是否已经满了
+     *
+     * @return 如果队列满的话返回true，否则返回false
+     */
+    public boolean isFull() {
+        if ((rear + 1) % size() == front) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * 判断队列是否为空
+     *
+     * @return 如果队列为空返回true，否则返回false
+     */
+    public boolean isEmpty() {
+        if (rear == -1 && front == -1) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * 入队操作
+     */
+    public void enQueue(int item) throws Exception {
+        if (isFull()) {
+            throw new Exception("队列已满");
+        } else if (isEmpty()) {
+            rear++;
+            front = rear;
+            array[rear] = item;
+        } else {
+            rear = (rear + 1) % size();
+            array[rear] = item;
+        }
+    }
+
+    /**
+     * 出队操作
+     */
+    public void deQueue() throws Exception {
+        if (isEmpty()) {
+            throw new Exception("队列为空");
+        } else if (front == rear) {
+            front = -1;
+            rear = -1;
+        } else {
+            front = (front + 1) % size();
+        }
+    }
+
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("(");
+        for (int i = 0; i <= size() - 1; i++) {
+            sb.append(array[i]);
+            sb.append(", ");
+        }
+        sb.append(")");
+        return sb.toString();
+    }
+}

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/queue/Josephus.java

@@ -0,0 +1,31 @@
+package com.johnChnia.coding2017.basic.queue;
+
+
+import com.johnChnia.coding2017.basic.ArrayList;
+import com.johnChnia.coding2017.basic.List;
+
+/**
+ * 用Queue来实现Josephus问题
+ * 在这个古老的问题当中， N个深陷绝境的人一致同意用这种方式减少生存人数：  N个人围成一圈（位置记为0到N-1）， 并且从第一个人报数， 报到M的人会被杀死， 直到最后一个人留下来
+ * 该方法返回一个List， 包含了被杀死人的次序
+ * 参考 http://interactivepython.org/courselib/static/pythonds/BasicDS/SimulationHotPotato.html
+ *
+ * @author john
+ */
+public class Josephus {
+
+    public static List<Integer> execute(int n, int m) {
+        ArrayList<Integer> arrayList = new ArrayList<>();
+        Queue<Integer> queue = new Queue<>();
+        for (int i = 0; i < n; i++) {
+            queue.add(i);
+        }
+        while (queue.size() > 1) {
+            for (int i = 0; i < m - 1; i++) {
+                queue.add(queue.remove());
+            }
+            arrayList.add(queue.remove());
+        }
+        return arrayList;
+    }
+}

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/queue/JosephusTest.java

@@ -0,0 +1,27 @@
+package com.johnChnia.coding2017.basic.queue;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+
+
+public class JosephusTest {
+
+	@Before
+	public void setUp() throws Exception {
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	@Test
+	public void testExecute() {
+
+		Assert.assertEquals("[1, 3, 5, 0, 4, 2, ]", Josephus.execute(7, 2).toString());
+
+	}
+
+}

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/Queue.java → group24/315863321/src/main/java/com/johnChnia/coding2017/basic/queue/Queue.java

@@ -1,4 +1,6 @@
-package com.johnChnia.coding2017.basic;
+package com.johnChnia.coding2017.basic.queue;
+
+import com.johnChnia.coding2017.basic.ArrayList;
 
 import java.util.NoSuchElementException;