Refactor problem

src/project_euler_python/problems_001_050/Problem014.py

@@ -12,14 +12,14 @@ https://projecteuler.net/problem=14
 from project_euler_python.utils import timeit
 
 
-def chain_length(n, terms):
+def chain_length(n: int, terms: dict[int, int]) -> int:
     length = 0
     while n != 1:
         if n in terms:
             length += terms[n]
             break
         if n % 2 == 0:
-            n = n / 2
+            n //= 2
         else:
             n = 3 * n + 1
         length += 1
@@ -27,7 +27,7 @@ def chain_length(n, terms):
 
 
 @timeit("Problem 014")
-def compute():
+def compute() -> int:
     """
     The following iterative sequence is defined for the set of positive
     integers:
@@ -49,15 +49,17 @@ def compute():
     NOTE: Once the chain starts the terms are allowed to go above one million.
     """
 
-    ans = 0
     limit = 1_000_000
-    score = 0
-    terms = dict()
-    for i in range(1, limit):
-        terms[i] = chain_length(i, terms)
-        if terms[i] > score:
-            score = terms[i]
-            ans = i
+    ans = 0
+    longest_length = 0
+    chain_lengths = {1: 0}
+
+    for start in range(2, limit):
+        current_length = chain_length(start, chain_lengths)
+        chain_lengths[start] = current_length
+        if current_length > longest_length:
+            ans = start
+            longest_length = current_length
 
     return ans