committed from zkp

pythonkd · pythonkd · commit b995b7abd305 · 2018-11-26T20:46:45.000+08:00
diff --git a/LeetCode/ArrayQueue.py b/LeetCode/ArrayQueue.py
@@ -0,0 +1,54 @@
+class Array:
+    def __init__(self, size=32):
+        self._size = size
+        self._items = [None]*32
+    def __getitem__(self, index):
+        return self._items[index]
+    def __setitem__(self, index, value):
+        self._items[index] = value
+    def __len__(self):
+        return self._size
+    def clear(self, value=None):
+        for i in range(len(self._items)):
+            self._items[i] = value
+    def __iter__(self):
+        for i in self._items:
+            yield i
+class FullError(Exception):
+    pass
+class ArrayQueue:
+    '''定长的队列，当队列满了之后再添加元素，会覆盖掉最后添加的一个元素。'''
+    def __init__(self, maxsize):
+        self.maxsize = maxsize
+        self.array = Array(maxsize)
+        self.head = 0
+        self.tail = 0
+    def push(self, value):
+        if len(self.array) > self.maxsize:
+            raise FullError('The queue is full')
+        self.array[self.head%self.maxsize] = value
+        self.head += 1
+    def pop(self):
+        value = self.array[self.tail%self.maxsize]
+        self.tail += 1
+        return value
+    def __len__(self):
+        return self.head - self.tail
+def test_array_queue():
+    size = 5
+    q = ArrayQueue(size)
+    for i in range(size):
+        q.push(i)
+    assert len(q) == size
+    assert q.pop() == 0
+    assert q.pop() == 1
+    q.push(5)
+    assert len(q) == 4
+    assert q.pop() == 2
+    assert q.pop() == 3
+    assert q.pop() == 4
+    assert q.pop() == 5
+    assert len(q) == 0
+    print('Test Successful')
+if __name__ == "__main__":
+    test_array_queue()
