Add type hints and default args to problem 15

project_euler/problem_15/sol1.py

@@ -6,34 +6,21 @@
 from math import factorial
 
 
-def lattice_paths(n):
+def solution(n: int = 20) -> int:
     """
-        Returns the number of paths possible in a n x n grid starting at top left
-        corner going to bottom right corner and being able to move right and down
-        only.
-
-    bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 50
-    1.008913445455642e+29
-    bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 25
-    126410606437752.0
-    bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 23
-    8233430727600.0
-    bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 15
-    155117520.0
-    bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 1
-    2.0
-
-        >>> lattice_paths(25)
-        126410606437752
-        >>> lattice_paths(23)
-        8233430727600
-        >>> lattice_paths(20)
-        137846528820
-        >>> lattice_paths(15)
-        155117520
-        >>> lattice_paths(1)
-        2
-
+    Returns the number of paths possible in a n x n grid starting at top left
+    corner going to bottom right corner and being able to move right and down
+    only.
+    >>> solution(25)
+    126410606437752
+    >>> solution(23)
+    8233430727600
+    >>> solution(20)
+    137846528820
+    >>> solution(15)
+    155117520
+    >>> solution(1)
+    2
     """
     n = 2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
     # 2, 3,...
@@ -46,10 +33,10 @@ def lattice_paths(n):
     import sys
 
     if len(sys.argv) == 1:
-        print(lattice_paths(20))
+        print(solution(20))
     else:
         try:
             n = int(sys.argv[1])
-            print(lattice_paths(n))
+            print(solution(n))
         except ValueError:
             print("Invalid entry - please enter a number.")