Added type hints to the Queue

OBJECTIVES.md

@@ -14,7 +14,7 @@
 	- Approximation algorithms
 	- Heuristics
 
-or even to more general scientific areas
+ or even to more general scientific areas
 
 	- Artificial intelligence
 	- Numerical computing

ands/algorithms/greedy/fractional_knapsack.py

@@ -17,7 +17,7 @@ def ask_objects():
     objects = []
     print("Welcome to the Fractional Knapsack problem!\n\n" +
           "You will tell me the objects that you have,\n" +
-          "their cost and their weight.\n\n" +
+          "their path_cost and their weight.\n\n" +
           "You should also tell me after that\n"
           "how much weight you can carry with you.\n\n" +
           "I will tell you then which items or\n" +
@@ -38,7 +38,7 @@ def ask_objects():
             print("-" * 40, end="\n\n")
 
     for obj in objects:
-        # adding as forth property of each object its cost/weight ratio
+        # adding as forth property of each object its path_cost/weight ratio
         obj.append(obj[1] / obj[2])
 
     objects.sort(key=operator.itemgetter(3), reverse=True)

ands/ds/Queue.py

@@ -45,22 +45,22 @@ def __init__(self, ls=None):
             ls = []
         self.q = deque(ls)
 
-    def enqueue(self, elem) -> None:
+    def enqueue(self, elem: object) -> None:
         """Adds `elem` to the end of this queue.
 
         Assumes `elem` is not None."""
         assert elem is not None
         self.q.append(elem)
 
-    def dequeue(self):
+    def dequeue(self) -> object:
         """Returns the first element of this queue."""
         return None if self.is_empty() else self.q.popleft()
 
-    def is_empty(self):
+    def is_empty(self) -> bool:
         """Returns `True` if this queue is empty, `False` otherwise."""
         return self.size() == 0
 
-    def size(self):
+    def size(self) -> int:
         """Returns the size of this queue."""
         return len(self.q)
 

tests/ds/test_Queue.py

@@ -65,15 +65,12 @@ def test_dequeue_one(self):
         self.assertTrue(q.is_empty())
 
     def test_dequeue_many(self):
-
-        r = randint(2, 100)
-        ls = [randint(-100, 100) for _ in range(r)]
-
+        ls = [2, 3, 5, 7, 11, 13]
         q = Queue(ls)
 
-        for _ in range(r):
+        for i in range(len(ls)):
             elem = q.dequeue()
-            self.assertIsNotNone(elem)
+            self.assertEqual(elem, ls[i])
 
         self.assertTrue(q.is_empty())