add util.py

projects/social/util.py

@@ -0,0 +1,28 @@
+
+# Note: This Queue class is sub-optimal. Why?
+class Queue():
+    def __init__(self):
+        self.queue = []
+    def enqueue(self, value):
+        self.queue.append(value)
+    def dequeue(self):
+        if self.size() > 0:
+            return self.queue.pop(0)
+        else:
+            return None
+    def size(self):
+        return len(self.queue)
+
+class Stack():
+    def __init__(self):
+        self.stack = []
+    def push(self, value):
+        self.stack.append(value)
+    def pop(self):
+        if self.size() > 0:
+            return self.stack.pop()
+        else:
+            return None
+    def size(self):
+        return len(self.stack)
+