From e314d433e66a6177c8a17e3fca5acc59005e1b06 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Tue, 29 Jan 2019 16:18:10 -0600
Subject: Network Packet done!

It's not too bad, since I worked things out in Java first. 2
things are of note: 1. Java Deque's pop is Python Deque's
popleft. 2. I didn't use an iterator to remove items. It
seemed to work fine.
---
 sources/network_packet.py   | 63 +++++++++++++++++++++++++++++++++++++++++++++
 tests/network_packetTest.py | 52 +++++++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 sources/network_packet.py
 create mode 100644 tests/network_packetTest.py

diff --git a/sources/network_packet.py b/sources/network_packet.py
new file mode 100644
index 0000000..46ac2fb
--- /dev/null
+++ b/sources/network_packet.py
@@ -0,0 +1,63 @@
+# python3
+
+from collections import namedtuple, deque
+
+Request = namedtuple("Request", ["arrived_at", "time_to_process"])
+Response = namedtuple("Response", ["was_dropped", "started_at"])
+
+
+class Buffer:
+    def __init__(self, capacity):
+        self.capacity = capacity
+        self.finish_time = deque()
+        self.running_time_counter = 0
+
+    def process(self, request):
+        if self.running_time_counter < request.arrived_at:
+            if len(self.finish_time) == 0:
+                self.running_time_counter = request.arrived_at
+            elif self.finish_time[-1] < request.arrived_at:
+                self.running_time_counter = request.arrived_at
+
+        while len(self.finish_time) > 0:
+            j = self.finish_time[0]
+            if j <= request.arrived_at:
+                self.finish_time.popleft()
+            else:
+                break
+
+        if len(self.finish_time) >= self.capacity:
+            return Response(True, -1)
+
+        response = Response(False, self.running_time_counter)
+        self.running_time_counter = self.running_time_counter + request.time_to_process
+        if len(self.finish_time) > 0:
+            self.finish_time.append(self.finish_time[-1] + request.time_to_process)
+        else:
+            self.finish_time.append(self.running_time_counter)
+        return response
+
+
+def process_requests(requests, buffer):
+    responses = []
+    for request in requests:
+        responses.append(buffer.process(request))
+    return responses
+
+
+def main():
+    buffer_size, n_requests = map(int, input().split())
+    requests = []
+    for _ in range(n_requests):
+        arrived_at, time_to_process = map(int, input().split())
+        requests.append(Request(arrived_at, time_to_process))
+
+    buffer = Buffer(buffer_size)
+    responses = process_requests(requests, buffer)
+
+    for response in responses:
+        print(response.started_at if not response.was_dropped else -1)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/network_packetTest.py b/tests/network_packetTest.py
new file mode 100644
index 0000000..c5bb709
--- /dev/null
+++ b/tests/network_packetTest.py
@@ -0,0 +1,52 @@
+import unittest
+
+from collections import namedtuple
+
+Request = namedtuple("Request", ["arrived_at", "time_to_process"])
+Response = namedtuple("Response", ["was_dropped", "started_at"])
+
+import sources.network_packet
+from sources.network_packet import process_requests
+
+
+class MyTestCase(unittest.TestCase):
+    def test(self):
+        buffer_max_size = 1
+        buf = sources.network_packet.Buffer(buffer_max_size)
+        requests = []
+        responses = process_requests(requests, buf)
+        self.assertEqual(0, len(responses))
+
+    def test1(self):
+        buffer_max_size = 1
+        buf = sources.network_packet.Buffer(buffer_max_size)
+        requests = [Request(0, 1)]
+        responses = process_requests(requests, buf)
+        self.assertEqual(1, len(responses))
+        self.assertFalse(responses[0].was_dropped)
+        self.assertEqual(0, responses[0].started_at)
+
+    def test2(self):
+        buffer_max_size = 1
+        buf = sources.network_packet.Buffer(buffer_max_size)
+        requests = [Request(0, 1), Request(0, 1)]
+        responses = process_requests(requests, buf)
+        self.assertEqual(2, len(responses))
+        self.assertFalse(responses[0].was_dropped)
+        self.assertEqual(0, responses[0].started_at)
+        self.assertTrue(responses[1].was_dropped)
+
+    def test3(self):
+        buffer_max_size = 1
+        buf = sources.network_packet.Buffer(buffer_max_size)
+        requests = [Request(0, 1), Request(1, 1)]
+        responses = process_requests(requests, buf)
+        self.assertEqual(2, len(responses))
+        self.assertFalse(responses[0].was_dropped)
+        self.assertEqual(0, responses[0].started_at)
+        self.assertFalse(responses[1].was_dropped)
+        self.assertEqual(1, responses[1].started_at)
+
+
+if __name__ == '__main__':
+    unittest.main()
-- 
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