Added rind buffer algorithm in python 231

Author: WindowGenerator

.gitignore

@@ -1 +1,2 @@
 .metals
+__pycache__/

README.md

@@ -2328,6 +2328,64 @@ In order to achieve greater coverage and encourage more people to contribute to
                 </a>
             </td>
         </tr>
+        <tr>
+            <td><a href="https://en.wikipedia.org/wiki/Circular_buffer">Ring Buffer</a></td>
+            <td> <!-- C -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- C++ -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Java -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Python -->
+                <a href="./src/python/ring_buffer.py">
+                    <img align="center" height="25" src="./logos/python.svg" />
+                </a>
+            </td>
+            <td> <!-- Go -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Ruby -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- JavaScript -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Swift -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Rust -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Scala -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Kotlin -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+        </tr>
         <tr>
             <td><a href="https://en.wikipedia.org/wiki/Hash_table">Hash Table</a></td>
             <td> <!-- C -->

src/python/ring_buffer.py

@@ -0,0 +1,133 @@
+from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+
+class RingBuffer(Generic[T]):
+    def __init__(self, capacity: int) -> None:
+        self._capacity = capacity
+        self._init_buffer()
+
+    def __str__(self) -> str:
+        if self.is_empty():
+            return "[]"
+
+        if self._tail > self._head:
+            buffer_state = self._buffer[self._head : self._tail]
+        else:
+            buffer_state = self._buffer[self._head :] + self._buffer[: self._tail]
+        return str(buffer_state)
+
+    def __repr__(self) -> str:
+        return self.__str__()
+
+    def __len__(self) -> int:
+        return self._size
+
+    def _init_buffer(self) -> None:
+        self._buffer = [None] * self._capacity
+        self._head = 0
+        self._tail = 0
+        self._size = 0
+
+    def clear(self) -> None:
+        self._init_buffer()
+
+    def push(self, item: T) -> None:
+        if self.is_full():
+            raise IndexError("Ring buffer is full")
+
+        self._buffer[self._tail] = item
+        self._tail = (self._tail + 1) % self._capacity
+        self._size = min(self._size + 1, self._capacity)
+
+    def get(self) -> T:
+        if self.is_empty():
+            raise IndexError("Ring buffer is empty")
+
+        item = self._buffer[self._head]
+        self._head = (self._head + 1) % self._capacity
+        self._size -= 1
+        return item
+
+    def is_full(self) -> bool:
+        return self._size == self._capacity
+
+    def is_empty(self) -> bool:
+        return self._size == 0
+
+
+if __name__ == "__main__":
+    import unittest
+
+    class TestRingBuffer(unittest.TestCase):
+        def test_push(self):
+            ring_buffer = RingBuffer[int](3)
+            ring_buffer.push(7)
+            ring_buffer.push(3)
+            self.assertEqual("[7, 3]", str(ring_buffer))
+            ring_buffer.push(10)
+            self.assertEqual("[7, 3, 10]", str(ring_buffer))
+
+        def test_get(self):
+            ring_buffer = RingBuffer[int](3)
+            ring_buffer.push(17)
+            ring_buffer.push(35)
+            self.assertEqual(17, ring_buffer.get())
+            self.assertEqual(35, ring_buffer.get())
+
+        def test_clear(self):
+            ring_buffer = RingBuffer[int](3)
+            ring_buffer.push(6)
+            ring_buffer.push(11)
+            self.assertEqual("[6, 11]", str(ring_buffer))
+            ring_buffer.clear()
+            self.assertEqual("[]", str(ring_buffer))
+            self.assertEqual(0, len(ring_buffer))
+
+        def test_push_with_full_error(self):
+            ring_buffer = RingBuffer[int](1)
+            ring_buffer.push(7)
+            self.assertRaises(IndexError, ring_buffer.push, 9)
+
+            ring_buffer = RingBuffer[int](2)
+            ring_buffer.push(23)
+            ring_buffer.push(14)
+            self.assertRaises(IndexError, ring_buffer.push, 11)
+
+        def test_get_with_empty_error(self):
+            ring_buffer = RingBuffer[int](1)
+            self.assertRaises(IndexError, ring_buffer.get)
+            ring_buffer.push(15)
+            ring_buffer.get()
+            self.assertRaises(IndexError, ring_buffer.get)
+
+        def test_size(self):
+            ring_buffer = RingBuffer[int](3)
+            ring_buffer.push(5)
+            self.assertEqual(1, len(ring_buffer))
+            ring_buffer.push(3)
+            self.assertEqual(2, len(ring_buffer))
+            ring_buffer.get()
+            self.assertEqual(1, len(ring_buffer))
+
+        def test_str(self):
+            ring_buffer = RingBuffer[int](3)
+            self.assertEqual("[]", str(ring_buffer))
+            ring_buffer.push(10)
+            self.assertEqual("[10]", str(ring_buffer))
+            ring_buffer.get()
+            ring_buffer.push(11)
+            ring_buffer.push(9)
+            self.assertEqual("[11, 9]", str(ring_buffer))
+            ring_buffer.push(7)
+            self.assertEqual("[11, 9, 7]", str(ring_buffer))
+
+        def test_with_str_type(self):
+            ring_buffer = RingBuffer[str](3)
+            ring_buffer.push("mug")
+            ring_buffer.push("cup")
+            self.assertEqual("['mug', 'cup']", str(ring_buffer))
+
+    suite = unittest.TestLoader().loadTestsFromTestCase(TestRingBuffer)
+    unittest.TextTestRunner(verbosity=2).run(suite)