Adding doctests in stock_span_problem.py

data_structures/stacks/stock_span_problem.py

@@ -8,44 +8,46 @@
 """
 
 
-def calculation_span(price, s):
+def calculation_span(price: list[float]) -> list[float]:
+    """
+    Calculate the span values for a given list of stock prices.
+    Args:
+        price (list): List of stock prices.
+    Returns:
+    >>> price = [10, 4, 5, 90, 120, 80]
+    >>> calculation_span(price)
+    [1.0, 1.0, 2.0, 4.0, 5.0, 1.0]
+    >>> price = [100, 50, 60, 70, 80, 90]
+    >>> calculation_span(price)
+    [1.0, 1.0, 2.0, 3.0, 4.0, 5.0]
+    >>> price = [5, 4, 3, 2, 1]
+    >>> calculation_span(price)
+    [1.0, 1.0, 1.0, 1.0, 1.0]
+    >>> price = [1, 2, 3, 4, 5]
+    >>> calculation_span(price)
+    [1.0, 2.0, 3.0, 4.0, 5.0]
+    >>> price = [10, 20, 30, 40, 50]
+    >>> calculation_span(price)
+    [1.0, 2.0, 3.0, 4.0, 5.0]
+    >>> calculation_span(price=[100, 80, 60, 70, 60, 75, 85])
+    [1.0, 1.0, 1.0, 2.0, 1.0, 4.0, 6.0]
+    """
     n = len(price)
-    # Create a stack and push index of fist element to it
-    st = []
-    st.append(0)
-
-    # Span value of first element is always 1
-    s[0] = 1
-
-    # Calculate span values for rest of the elements
+    st = [0]
+    s = [1.0]
     for i in range(1, n):
-        # Pop elements from stack while stack is not
-        # empty and top of stack is smaller than price[i]
-        while len(st) > 0 and price[st[0]] <= price[i]:
+        while st and price[st[-1]] <= price[i]:
             st.pop()
-
-        # If stack becomes empty, then price[i] is greater
-        # than all elements on left of it, i.e. price[0],
-        # price[1], ..price[i-1]. Else the price[i]  is
-        # greater than elements after top of stack
-        s[i] = i + 1 if len(st) <= 0 else (i - st[0])
-
-        # Push this element to stack
+        s.append(float(i - st[-1] if st else i + 1))
         st.append(i)
+    return s
 
 
-# A utility function to print elements of array
-def print_array(arr, n):
-    for i in range(n):
-        print(arr[i], end=" ")
-
-
-# Driver program to test above function
-price = [10, 4, 5, 90, 120, 80]
-S = [0 for i in range(len(price) + 1)]
+price = [10.0, 4.0, 5.0, 90.0, 120.0, 80.0]
+S = calculation_span(price)
+print(S)
 
-# Fill the span values in array S[]
-calculation_span(price, S)
+if __name__ == "__main__":
+    import doctest
 
-# Print the calculated span values
-print_array(S, len(price))
+    doctest.testmod()