Add type hints in problems 21-30

Python/p021.py

@@ -13,8 +13,8 @@ from projecteuler import sum_of_divisors, timing
 
 
 @timing
-def p021():
+def p021() -> None:
-    sum_ = 0
+    _sum = 0
 
     for i in range(2, 10000):
         # Calculate the sum of proper divisors with the function
@@ -24,12 +24,12 @@ def p021():
         # If i!=n and the sum of proper divisors of n=i,
         # sum the pair of numbers and add it to the total.
         if i != n and sum_of_divisors(n) == i:
-            sum_ = sum_ + i + n
+            _sum = _sum + i + n
 
-    sum_ = sum_ // 2
+    _sum = _sum // 2
 
     print('Project Euler, Problem 21')
-    print(f'Answer: {sum_}')
+    print(f'Answer: {_sum}')
 
 
 if __name__ == '__main__':

Python/p022.py

@@ -14,7 +14,7 @@ from projecteuler import timing
 
 
 @timing
-def p022():
+def p022() -> None:
     try:
         with open('p022_names.txt', 'r', encoding='utf-8') as fp:
             names = list(fp.readline().replace('"', '').split(','))
@@ -24,7 +24,7 @@ def p022():
 
     names.sort()
 
-    sum_ = 0
+    _sum = 0
     i = 1
 
     # Calculate the score of each name an multiply by its position.
@@ -34,11 +34,11 @@ def p022():
         for j in range(l):
             score = score + ord(name[j]) - ord('A') + 1
         score = score * i
-        sum_ = sum_ + score
+        _sum = _sum + score
         i = i + 1
 
     print('Project Euler, Problem 22')
-    print(f'Answer: {sum_}')
+    print(f'Answer: {_sum}')
 
 
 if __name__ == '__main__':

Python/p023.py

@@ -15,12 +15,12 @@
 from projecteuler import sum_of_divisors, timing
 
 
-def is_abundant(n):
+def is_abundant(n: int) -> bool:
     return sum_of_divisors(n) > n
 
 
 @timing
-def p023():
+def p023() -> None:
     ab_nums = [False] * 28124
 
     # Find all abundant numbers smaller than 28123.
@@ -36,19 +36,20 @@ def p023():
         if ab_nums[i]:
             for j in range(i, 28123):
                 if ab_nums[j]:
-                    sum_ = i + j
+                    _sum = i + j
-                    if sum_ <= 28123:
-                        sums[sum_] = True
 
-    sum_ = 0
+                    if _sum <= 28123:
+                        sums[_sum] = True
+
+    _sum = 0
 
     # Sum every number that was not found as a sum of two abundant numbers.
     for i in range(1, 28124):
         if not sums[i]:
-            sum_ = sum_ + i
+            _sum = _sum + i
 
     print('Project Euler, Problem 23')
-    print(f'Answer: {sum_}')
+    print(f'Answer: {_sum}')
 
 
 if __name__ == '__main__':

Python/p024.py

@@ -13,7 +13,7 @@ from projecteuler import timing
 
 
 @timing
-def p024():
+def p024() -> None:
     # Generate all the permutations in lexicographic order and get the millionth one.
     perm = list(permutations('0123456789'))
     res = int(''.join(map(str, perm[999999])))

Python/p025.py

@@ -25,7 +25,7 @@ from projecteuler import timing
 
 
 @timing
-def p025():
+def p025() -> None:
     fib1 = 1
     fib2 = 1
     fibn = fib1 + fib2

Python/p026.py

@@ -20,8 +20,9 @@ from projecteuler import timing
 
 
 @timing
-def p026():
+def p026() -> None:
-    max_ = 0
+    _max = 0
+    max_n = -1
 
     for i in range(2, 1000):
         j = i
@@ -50,8 +51,8 @@ def p026():
                 k = k * 10
                 k = k + 9
 
-            if n > max_:
+            if n > _max:
-                max_ = n
+                _max = n
                 max_n = i
 
     print('Project Euler, Problem 26')

Python/p027.py

@@ -24,8 +24,8 @@ from projecteuler import is_prime, timing
 
 
 @timing
-def p027():
+def p027() -> None:
-    max_ = 0
+    _max = 0
 
     # Brute force approach, optimized by checking only values of b where b is prime.
     for a in range(-999, 1000):
@@ -44,8 +44,8 @@ def p027():
                     else:
                         break
 
-                if count > max_:
+                if count > _max:
-                    max_ = count
+                    _max = count
                     save_a = a
                     save_b = b
 

Python/p028.py

@@ -16,7 +16,7 @@ from projecteuler import timing
 
 
 @timing
-def p028():
+def p028() -> None:
     N = 1001
 
     limit = N * N
@@ -24,7 +24,7 @@ def p028():
     i = 0
     j = 1
     step = 0
-    sum_ = 1
+    _sum = 1
 
     # Starting with the central 1, it's easy to see that the next four numbers in the diagonal
     # are 1+2, 1+2+2, 1+2+2+2 and 1+2+2+2+2, then for the next four number the step is increased
@@ -34,11 +34,11 @@ def p028():
         if i == 0:
             step = step + 2
         j = j + step
-        sum_ = sum_ + j
+        _sum = _sum + j
         i = (i + 1) % 4
 
     print('Project Euler, Problem 28')
-    print(f'Answer: {sum_}')
+    print(f'Answer: {_sum}')
 
 
 if __name__ == '__main__':

Python/p029.py

@@ -19,17 +19,17 @@ from projecteuler import timing
 
 
 @timing
-def p029():
+def p029() -> None:
-    powers = zeros(9801)
+    _powers = zeros(9801)
 
     # Generate all the powers
     for i in range(2, 101):
         a = i
         for j in range(2, 101):
-            powers[(i-2)*99+j-2] = a ** j
+            _powers[(i-2)*99+j-2] = a ** j
 
     # Sort the values and count the different values.
-    powers = list(powers)
+    powers = list(_powers)
     powers.sort()
 
     count = 1

Python/p030.py

@@ -16,7 +16,7 @@ from projecteuler import timing
 
 
 @timing
-def p030():
+def p030() -> None:
     tot = 0
 
     # Straightforward brute force approach. The limit is chosen considering that
@@ -24,14 +24,14 @@ def p030():
     # of 5th power of its digits.
     for i in range(10, 354295):
         j = i
-        sum_ = 0
+        _sum = 0
 
         while j > 0:
             digit = j % 10
-            sum_ = sum_ + digit ** 5
+            _sum = _sum + digit ** 5
             j = j // 10
 
-        if sum_ == i:
+        if _sum == i:
             tot = tot + i
 
     print('Project Euler, Problem 30')