[Project Euler] Added type hints and refactored the code for Problem 14 (#3047)

* added type hints and refactored the code a bit

* made output statement more explicit

* used f-strings and updated type hints

* modified solution function to return an integer solution

* updated docstring

* Update sol1.py

* Update sol2.py

Co-authored-by: Dhruv <dhruvmanila@gmail.com>

project_euler/problem_14/sol1.py

@@ -1,4 +1,6 @@
 """
+Problem 14: https://projecteuler.net/problem=14
+
 Problem Statement:
 The following iterative sequence is defined for the set of positive integers:
 
@@ -17,7 +19,7 @@ Which starting number, under one million, produces the longest chain?
 """
 
 
-def solution(n):
+def solution(n: int = 1000000) -> int:
     """Returns the number under n that generates the longest sequence using the
     formula:
     n → n/2 (n is even)
@@ -25,13 +27,13 @@ def solution(n):
 
     # The code below has been commented due to slow execution affecting Travis.
     # >>> solution(1000000)
-    # {'counter': 525, 'largest_number': 837799}
+    # 837799
     >>> solution(200)
-    {'counter': 125, 'largest_number': 171}
+    171
     >>> solution(5000)
-    {'counter': 238, 'largest_number': 3711}
+    3711
     >>> solution(15000)
-    {'counter': 276, 'largest_number': 13255}
+    13255
     """
     largest_number = 0
     pre_counter = 0
@@ -51,11 +53,8 @@ def solution(n):
         if counter > pre_counter:
             largest_number = input1
             pre_counter = counter
-    return {"counter": pre_counter, "largest_number": largest_number}
+    return largest_number
 
 
 if __name__ == "__main__":
-    result = solution(int(input().strip()))
-    print(
-        ("Largest Number:", result["largest_number"], "->", result["counter"], "digits")
-    )
+    print(solution(int(input().strip())))