Merge pull request #33 from zndbl/master

2441547139 前三次作业，部分方法未完成

group26/2441547139/week1/collection/MyArrayList.java

@@ -0,0 +1,65 @@
+package week1.collection;
+
+import java.util.Arrays;
+/**
+ * Created by zndbl on 2017/3/11.
+ */
+public class MyArrayList {
+
+    private int size;
+    private Object[] arr;
+
+    public MyArrayList() {
+        this(10);
+    }
+
+    public MyArrayList(int oldLength) {
+        if(oldLength < 0) {
+            throw new RuntimeException("创建集合失败");
+        }
+        arr = new Object[oldLength];
+    }
+
+    public int size() {
+        return size;
+    }
+
+    /**
+     * 数组的长度扩充策略
+     */
+    public void ensureCapacity(int minCapatity ) {
+        int oldCapacity = arr.length;
+        if(minCapatity > oldCapacity) {
+            int newCapatity = 3 * oldCapacity / 2 + 1;
+            if(minCapatity > newCapatity) {
+                newCapatity = minCapatity;
+            }
+            arr = Arrays.copyOf(arr,newCapatity);
+        }
+    }
+
+    public void add(Object element) {
+        ensureCapacity(size+1);
+        arr[size++] = element;
+    }
+
+    public void add(int index, Object element) {
+        if(index < 0 || index > size) {
+            throw new RuntimeException("数组越界");
+        }
+        ensureCapacity(size+1);
+        System.arraycopy(arr,index,arr,index+1,size-index);
+        arr[index] = element;
+        size++;
+    }
+
+    public boolean remove(Object o) {
+        for(int i=0; i<size; i++) {
+            if(arr[i].equals(o)) {
+                int num = size - i - 1;
+                System.arraycopy(arr, i+1, arr, i, num);
+            }
+        }
+        return true;
+    }
+}

group26/2441547139/week1/collection/MyLinkedList.java

@@ -0,0 +1,115 @@
+package week1.collection;
+
+/**
+ * Created by zndbl on 2017/3/11.
+ */
+public class MyLinkedList {
+
+    private int size;
+    private Node first;
+    private Node last;
+
+    public static class Node{
+        Object item;
+        Node next;
+        Node prev;
+
+        public Node(Object item, Node next, Node prev) {
+            this.item = item;
+            this.next = next;
+            this.prev = prev;
+        }
+    }
+
+    public boolean add(Object element) {
+        addAtLast(element);
+        return true;
+    }
+
+    public void addAtLast(Object element) {
+        Node l = last;
+        Node node = new Node(element,null,l);
+        last = node;
+        if(l == null) {
+            first = node;
+        } else {
+            l.next = node;
+        }
+        size++;
+    }
+
+    public Node node(int index) {
+        if(index < size/2 ) {
+            Node cussor = first;
+            for (int i = 0; i < index ; i++) {
+                cussor = cussor.next;
+            }
+            return cussor;
+        } else {
+            Node cussor = last;
+            for (int i = size -1 ; i > index ; i--) {
+                cussor = cussor.prev;
+            }
+            return cussor;
+        }
+    }
+
+    public Object get(int index) {
+        checkRange(index);
+        return node(index).item;
+    }
+
+    public void checkRange(int index) {
+        if(index >= size || index < 0) {
+            throw new RuntimeException("index超过界限");
+        }
+    }
+
+    public int indexOf(Object element) {
+        Node cussor = first;
+        int count = 0;
+        while (cussor != null) {
+            if(element.equals(cussor.item)) {
+                return count;
+            }
+            count++;
+            cussor = cussor.next;
+        }
+        return -1;
+    }
+
+    public boolean remove(Object o) {
+        int index = indexOf(o);
+        if(index < 0) {
+            return false;
+        }
+        deleteLink(index);
+        return true;
+    }
+
+    public Object deleteLink(int index) {
+        Node l = node(index);
+        Object item = l.item;
+        Node prevNode = l.prev;
+        Node nextNode = l.next;
+
+        if(prevNode == null) {
+            first = nextNode;
+        } else {
+            prevNode.next = nextNode;
+            l.next = null;
+        }
+        if(nextNode == null) {
+            last = prevNode;
+        } else {
+            nextNode.prev = prevNode;
+            l.prev = null;
+        }
+        size--;
+        l.item = null;
+        return item;
+
+    }
+
+
+}

group26/2441547139/week1/collection/MyQueue.java

@@ -0,0 +1,29 @@
+package week1.collection;
+
+/**
+ * Created by zndbl on 2017/3/12.
+ */
+public class MyQueue {
+
+    private Object[] data;
+    private int head;
+    private int tail;
+
+    public MyQueue() {
+        data =  new Object[10];
+        head = 1;
+        tail = 1;
+    }
+
+    public void put(Object obj) {
+        data[tail] = obj;
+        tail++;
+    }
+
+    public Object get() {
+        Object obj = data[head];
+        head++;
+        return obj;
+    }
+
+}

group26/2441547139/week1/collection/MyStack.java

@@ -0,0 +1,29 @@
+package week1.collection;
+
+/**
+ * Created by zndbl on 2017/3/12.
+ */
+public class MyStack {
+
+    private Object[] data;
+    private int top;
+
+    public MyStack() {
+        data = new Object[100];
+        top = -1;
+    }
+
+    public void put(Object t) {
+        data[data.length] = t;
+        top++;
+    }
+
+    public Object pop() {
+        if(top < 0) {
+            return null;
+        }
+        Object object = data[top];
+        top--;
+        return object;
+    }
+}