Merge pull request #47 from gitferry/master

增加了入队时进行数据迁移的代码

python/09_queue/array_queue.py

@@ -16,9 +16,16 @@ class ArrayQueue:
         self._tail = 0
 
     def enqueue(self, item: str) -> bool:
-        if self._tail == self._capacity: return False
+        if self._tail == self._capacity:
+            if self._head == 0:
+                return False
+            else:
+                for i in range(0, self._tail - self._head):
+                    self._data[i] = self._items[i + self._head]
+                self._tail = self._tail - self._head
+                self._head = 0
         
-        self._items.append(item)
+        self._items.insert(self._tail, item)
         self._tail += 1
         return True