添加队列的实现

chenweijie · chenweijie · commit d81a1253ffb7 · 2019-03-07T01:18:05.000+08:00
diff --git a/src/main/java/com/chen/dataStructure/queue/MyQueue.java b/src/main/java/com/chen/dataStructure/queue/MyQueue.java
@@ -0,0 +1,147 @@
+package com.chen.dataStructure.queue;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-03-07 12:13 AM
+ */
+public class MyQueue {
+
+    private Object[] queArray;
+
+    /**
+     * 队列总大小
+     */
+    private int maxSize;
+
+    /**
+     * 前端
+     */
+    private int front;
+
+    /**
+     * 后端
+     */
+    private int fear;
+
+    /**
+     * 队列中实际元素个数
+     */
+    private int nItems;
+
+    public MyQueue(int s) {
+        this.maxSize = s;
+        this.queArray = new Object[maxSize];
+        front = 0;
+        fear = -1;
+        nItems = 0;
+    }
+
+
+    /**
+     * 返回队列的大小
+     *
+     * @return
+     */
+    public int getSize() {
+        return nItems;
+    }
+
+    /**
+     * 队列是否为空
+     *
+     * @return
+     */
+    public boolean isEmpty() {
+        return nItems == 0;
+    }
+
+
+    /**
+     * 队列是否满了
+     *
+     * @return
+     */
+    public boolean isFull() {
+        return maxSize == nItems;
+    }
+
+    /**
+     * 查看队头元素
+     *
+     * @return
+     */
+    public Object peekFront() {
+        return queArray[front];
+    }
+
+
+    /**
+     * 移除元素
+     *
+     * @return
+     */
+    public Object remove() {
+
+        Object removeValue = null;
+        if (!isEmpty()) {
+            removeValue = peekFront();
+            front++;
+            if (front == maxSize) {
+                front = 0;
+            }
+            nItems--;
+            return removeValue;
+        }
+        return removeValue;
+    }
+
+
+
+    /**
+     * 队列中新增元素
+     *
+     * @param value
+     */
+    public void insert(Object value) {
+
+        if (isFull()) {
+            System.out.println("队列已满！！！");
+        } else {
+            if (fear == maxSize - 1) {
+                fear = -1;
+            }
+            //队尾指针加1，然后在队尾指针处插入新的数据
+            queArray[++fear] = value;
+            nItems++;
+        }
+    }
+
+
+    public static void main(String[] args) {
+
+        MyQueue myQueue = new MyQueue(4);
+
+        myQueue.insert(10);
+        myQueue.insert(20);
+        myQueue.insert(30);
+        myQueue.insert(40);
+
+        //获取队头元素
+        System.out.println("myQueue.peekFront():" + myQueue.peekFront());
+
+        //移除元素
+        myQueue.remove();
+
+        //插入元素
+        myQueue.insert(50);
+        myQueue.insert(60);
+
+        for (Object a : myQueue.queArray) {
+            System.out.println("a:" + a);
+        }
+    }
+
+
+
+
+}
diff --git a/src/main/java/com/chen/dataStructure/queue/PriorityQue.java b/src/main/java/com/chen/dataStructure/queue/PriorityQue.java
@@ -0,0 +1,85 @@
+package com.chen.dataStructure.queue;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-03-07 12:51 AM
+ */
+public class PriorityQue {
+
+
+    private int maxSize;
+
+    private int[] priQueArray;
+
+    private int nItems;
+
+
+    public PriorityQue(int s) {
+        this.maxSize = s;
+        this.priQueArray = new int[maxSize];
+        this.nItems = 0;
+    }
+
+
+    /**
+     * 元素是否满了
+     *
+     * @return
+     */
+    public boolean isFull() {
+        return maxSize == nItems;
+    }
+
+    /**
+     * 队列是否为空
+     *
+     * @return
+     */
+    public boolean isEmpty() {
+        return nItems == 0;
+    }
+
+
+    /**
+     * 查看优先级最高的元素
+     *
+     * @return
+     */
+    public int peekMin() {
+        return priQueArray[nItems - 1];
+    }
+
+    public void insert(int value) {
+
+        if (maxSize == nItems) {
+            System.out.println("队列已满！");
+        }
+
+        int j = 0;
+
+        if (nItems == 0) {
+            priQueArray[nItems++] = value;
+        } else {
+            //选择的排序方法是插入排序，按照从大到小的顺序排列，越小的越在队列的顶端
+            while (j >= 0 && value > priQueArray[j]) {
+                priQueArray[j + 1] = priQueArray[j];
+                j--;
+            }
+        }
+        priQueArray[j + 1] = value;
+        nItems++;
+    }
+
+    //移除数据,由于是按照大小排序的，所以移除数据我们指针向下移动
+    //被移除的地方由于是int类型的，不能设置为null，这里的做法是设置为 -1
+    public int remove() {
+
+        int k = nItems - 1;
+        int value = priQueArray[k];
+        priQueArray[k] = -1;
+        nItems--;
+        return value;
+    }
+
+
+}
