Refactor problem

src/project_euler_python/problems_001_050/Problem008.py

@@ -9,8 +9,9 @@ Solution for problem 008 of Project Euler
 https://projecteuler.net/problem=8
 """
 
-import collections
+from collections import deque
 from itertools import islice
+from math import prod
 
 from project_euler_python.utils import timeit
 
@@ -19,7 +20,7 @@ from project_euler_python.utils import timeit
 def sliding_window(iterable, n):
     # sliding_window('ABCDEFG', 4) -> ABCD BCDE CDEF DEFG
     it = iter(iterable)
-    window = collections.deque(islice(it, n), maxlen=n)
+    window = deque(islice(it, n), maxlen=n)
     if len(window) == n:
         yield tuple(window)
     for x in it:
@@ -65,12 +66,10 @@ def compute():
     num = NUM.replace("\n", "").replace(" ", "")
     adjacent_digits = 13
     ans = 0
-    for nums in sliding_window(num, adjacent_digits):
+
-        prod = 1
+    for digits in sliding_window(num, adjacent_digits):
-        for num in nums:
+        window_product = prod(int(digit) for digit in digits)
-            prod *= int(num)
+        ans = max(ans, window_product)
-        if prod > ans:
-            ans = prod
 
     return ans
 

src/project_euler_python/problems_001_050/Problem009.py

@@ -24,9 +24,9 @@ def compute():
     Find the product abc.
     """
 
-    upper_limit = 1000
+    upper_limit = 1000 + 1
-    for a in range(1, upper_limit + 1):
+    for a in range(1, upper_limit):
-        for b in range(a + 1, upper_limit + 1):
+        for b in range(a + 1, upper_limit):
             c = upper_limit - a - b
             if a * a + b * b == c * c:
                 # It is now implied that b < c, because we have a > 0

src/project_euler_python/problems_001_050/Problem012.py

@@ -9,7 +9,7 @@ Solution for problem 012 of Project Euler
 https://projecteuler.net/problem=12
 """
 
-from itertools import count
+from itertools import accumulate, count
 from math import floor, sqrt
 
 from project_euler_python.utils import timeit
@@ -53,12 +53,10 @@ def compute():
     divisors?
     """
 
-    triangle = 0
+    limit = 500
-    for i in count(1):
+    for triangle in accumulate(count(1)):
-        # This is the ith triangle number, i.e. num = 1 + 2 + ... + i =
+        # This is the ith triangle number, i.e. num = 1 + 2 + ... + i = i*(i+1)/2
-        # = i*(i+1)/2
+        if num_divisors(triangle) > limit:
-        triangle += i
-        if num_divisors(triangle) > 500:
             return str(triangle)
 
 

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
+    ans = 0
-    terms = dict()
+    longest_length = 0
-    for i in range(1, limit):
+    chain_lengths = {1: 0}
-        terms[i] = chain_length(i, terms)
+
-        if terms[i] > score:
+    for start in range(2, limit):
-            score = terms[i]
+        current_length = chain_length(start, chain_lengths)
-            ans = i
+        chain_lengths[start] = current_length
+        if current_length > longest_length:
+            ans = start
+            longest_length = current_length
 
     return ans