ArrayQueue: Add queue implementation using array

Author: cszach

src/main/lists/ArrayQueue.java

@@ -0,0 +1,58 @@
+/**
+ * An implementation of queue using a static array.
+ *
+ * <p>
+ * Operations and their time complexities are:
+ *   <ul>
+ *     <li><code>enqueue</code>: O(1)</li>
+ *     <li><code>dequeue</code>: O(n)</li>
+ *     <li><code>peek</code>: O(1)</li>
+ *   </ul>
+ */
+public class ArrayQueue<T> {
+  private Object[] array;
+  private int length;
+
+  public ArrayQueue(int maxLength) {
+    this.array = new Object[maxLength];
+    this.length = 0;
+  }
+
+  public ArrayQueue<T> enqueue(T data) {
+    if (this.length == this.array.length)
+      return this;
+
+    this.array[this.length++] = data;
+    return this;
+  }
+
+  public ArrayQueue<T> dequeue() {
+    if (this.length == 0)
+      return this;
+
+    int i;
+    for (i = 1; i < this.length; i++)
+      this.array[i - 1] = this.array[i];
+
+    this.array[i - 1] = null;
+    this.length--;
+    return this;
+  }
+
+  @SuppressWarnings("unchecked")
+  public T peek() {
+    return (T) this.array[0];
+  }
+
+  public static void main(String[] args) {
+    ArrayQueue<Integer> queue = new ArrayQueue<Integer>(10);
+
+    for (int i = 0; i < 15; i++)
+      queue.enqueue(i);
+
+    for (int i = 0; i < 20; i++) {
+      System.out.println(queue.peek());
+      queue.dequeue();
+    }
+  }
+}