Merge branch 'master' into add-gosper-curve

Author: badtommy67

CONTRIBUTING.md

@@ -159,7 +159,7 @@ We want your work to be readable by others; therefore, we encourage you to note
   starting_value = int(input("Please enter a starting value: ").strip())
   ```
 
-  The use of [Python type hints](https://docs.python.org/3/library/typing.html) is encouraged for function parameters and return values.  Our automated testing will run [mypy](http://mypy-lang.org) so run that locally before making your submission.
+  The use of [Python type hints](https://docs.python.org/3/library/typing.html) is encouraged for function parameters and return values.  Our automated testing will run [mypy](https://mypy-lang.org) so run that locally before making your submission.
 
   ```python
   def sum_ab(a: int, b: int) -> int:

backtracking/generate_parentheses_iterative.py

@@ -1,11 +1,12 @@
-def generate_parentheses_iterative(length: int) -> list:
+def generate_parentheses_iterative(length: int) -> list[str]:
     """
     Generate all valid combinations of parentheses (Iterative Approach).
 
     The algorithm works as follows:
     1. Initialize an empty list to store the combinations.
     2. Initialize a stack to keep track of partial combinations.
-    3. Start with empty string and push it onstack along with the counts of '(' and ')'.
+    3. Start with empty string and push it on stack along with
+       the counts of '(' and ')'.
     4. While the stack is not empty:
         a. Pop a partial combination and its open and close counts from the stack.
         b. If the combination length is equal to 2*length, add it to the result.
@@ -34,8 +35,11 @@ def generate_parentheses_iterative(length: int) -> list:
     >>> generate_parentheses_iterative(0)
     ['']
     """
-    result = []
-    stack = []
+    if length == 0:
+        return [""]
+
+    result: list[str] = []
+    stack: list[tuple[str, int, int]] = []
 
     # Each element in stack is a tuple (current_combination, open_count, close_count)
     stack.append(("", 0, 0))
@@ -45,6 +49,7 @@ def generate_parentheses_iterative(length: int) -> list:
 
         if len(current_combination) == 2 * length:
             result.append(current_combination)
+            continue
 
         if open_count < length:
             stack.append((current_combination + "(", open_count + 1, close_count))

maths/fibonacci.py

@@ -91,15 +91,15 @@ def fib_iterative(n: int) -> list[int]:
 def fib_recursive(n: int) -> list[int]:
     """
     Calculates the first n (0-indexed) Fibonacci numbers using recursion
-    >>> fib_iterative(0)
+    >>> fib_recursive(0)
     [0]
-    >>> fib_iterative(1)
+    >>> fib_recursive(1)
     [0, 1]
-    >>> fib_iterative(5)
+    >>> fib_recursive(5)
     [0, 1, 1, 2, 3, 5]
-    >>> fib_iterative(10)
+    >>> fib_recursive(10)
     [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
-    >>> fib_iterative(-1)
+    >>> fib_recursive(-1)
     Traceback (most recent call last):
         ...
     ValueError: n is negative
@@ -119,7 +119,7 @@ def fib_recursive_term(i: int) -> int:
         >>> fib_recursive_term(-1)
         Traceback (most recent call last):
             ...
-        Exception: n is negative
+        ValueError: n is negative
         """
         if i < 0:
             raise ValueError("n is negative")
@@ -135,15 +135,15 @@ def fib_recursive_term(i: int) -> int:
 def fib_recursive_cached(n: int) -> list[int]:
     """
     Calculates the first n (0-indexed) Fibonacci numbers using recursion
-    >>> fib_iterative(0)
+    >>> fib_recursive_cached(0)
     [0]
-    >>> fib_iterative(1)
+    >>> fib_recursive_cached(1)
     [0, 1]
-    >>> fib_iterative(5)
+    >>> fib_recursive_cached(5)
     [0, 1, 1, 2, 3, 5]
-    >>> fib_iterative(10)
+    >>> fib_recursive_cached(10)
     [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
-    >>> fib_iterative(-1)
+    >>> fib_recursive_cached(-1)
     Traceback (most recent call last):
         ...
     ValueError: n is negative
@@ -176,7 +176,7 @@ def fib_memoization(n: int) -> list[int]:
     [0, 1, 1, 2, 3, 5]
     >>> fib_memoization(10)
     [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
-    >>> fib_iterative(-1)
+    >>> fib_memoization(-1)
     Traceback (most recent call last):
         ...
     ValueError: n is negative

maths/greatest_common_divisor.py

@@ -30,6 +30,8 @@ def greatest_common_divisor(a: int, b: int) -> int:
     3
     >>> greatest_common_divisor(-3, -9)
     3
+    >>> greatest_common_divisor(0, 0)
+    0
     """
     return abs(b) if a == 0 else greatest_common_divisor(b % a, a)
 
@@ -50,6 +52,8 @@ def gcd_by_iterative(x: int, y: int) -> int:
     1
     >>> gcd_by_iterative(11, 37)
     1
+    >>> gcd_by_iterative(0, 0)
+    0
     """
     while y:  # --> when y=0 then loop will terminate and return x as final GCD.
         x, y = y, x % y

maths/matrix_exponentiation.py

@@ -11,15 +11,15 @@
 
 
 class Matrix:
-    def __init__(self, arg):
+    def __init__(self, arg: list[list] | int) -> None:
         if isinstance(arg, list):  # Initializes a matrix identical to the one provided.
             self.t = arg
             self.n = len(arg)
         else:  # Initializes a square matrix of the given size and set values to zero.
             self.n = arg
             self.t = [[0 for _ in range(self.n)] for _ in range(self.n)]
 
-    def __mul__(self, b):
+    def __mul__(self, b: Matrix) -> Matrix:
         matrix = Matrix(self.n)
         for i in range(self.n):
             for j in range(self.n):
@@ -28,7 +28,7 @@ def __mul__(self, b):
         return matrix
 
 
-def modular_exponentiation(a, b):
+def modular_exponentiation(a: Matrix, b: int) -> Matrix:
     matrix = Matrix([[1, 0], [0, 1]])
     while b > 0:
         if b & 1:
@@ -38,7 +38,7 @@ def modular_exponentiation(a, b):
     return matrix
 
 
-def fibonacci_with_matrix_exponentiation(n, f1, f2):
+def fibonacci_with_matrix_exponentiation(n: int, f1: int, f2: int) -> int:
     """
     Returns the nth number of the Fibonacci sequence that
     starts with f1 and f2
@@ -64,7 +64,7 @@ def fibonacci_with_matrix_exponentiation(n, f1, f2):
     return f2 * matrix.t[0][0] + f1 * matrix.t[0][1]
 
 
-def simple_fibonacci(n, f1, f2):
+def simple_fibonacci(n: int, f1: int, f2: int) -> int:
     """
     Returns the nth number of the Fibonacci sequence that
     starts with f1 and f2
@@ -95,7 +95,7 @@ def simple_fibonacci(n, f1, f2):
     return f2
 
 
-def matrix_exponentiation_time():
+def matrix_exponentiation_time() -> float:
     setup = """
 from random import randint
 from __main__ import fibonacci_with_matrix_exponentiation
@@ -106,7 +106,7 @@ def matrix_exponentiation_time():
     return exec_time
 
 
-def simple_fibonacci_time():
+def simple_fibonacci_time() -> float:
     setup = """
 from random import randint
 from __main__ import simple_fibonacci
@@ -119,7 +119,7 @@ def simple_fibonacci_time():
     return exec_time
 
 
-def main():
+def main() -> None:
     matrix_exponentiation_time()
     simple_fibonacci_time()
 

maths/modular_division.py

@@ -28,9 +28,13 @@ def modular_division(a: int, b: int, n: int) -> int:
     4
 
     """
-    assert n > 1
-    assert a > 0
-    assert greatest_common_divisor(a, n) == 1
+    if n <= 1:
+        raise ValueError("Modulus n must be greater than 1")
+    if a <= 0:
+        raise ValueError("Divisor a must be a positive integer")
+    if greatest_common_divisor(a, n) != 1:
+        raise ValueError("a and n must be coprime (gcd(a, n) = 1)")
+
     (_d, _t, s) = extended_gcd(n, a)  # Implemented below
     x = (b * s) % n
     return x

searches/binary_search.py

@@ -10,9 +10,8 @@
 python3 binary_search.py
 """
 
-from __future__ import annotations
-
 import bisect
+from itertools import pairwise
 
 
 def bisect_left(
@@ -198,7 +197,7 @@ def binary_search(sorted_collection: list[int], item: int) -> int:
     >>> binary_search([0, 5, 7, 10, 15], 6)
     -1
     """
-    if list(sorted_collection) != sorted(sorted_collection):
+    if any(a > b for a, b in pairwise(sorted_collection)):
         raise ValueError("sorted_collection must be sorted in ascending order")
     left = 0
     right = len(sorted_collection) - 1

searches/linear_search.py

@@ -1,5 +1,5 @@
 """
-This is pure Python implementation of linear search algorithm
+This is a pure Python implementation of the linear search algorithm.
 
 For doctests run following command:
 python3 -m doctest -v linear_search.py
@@ -12,8 +12,8 @@
 def linear_search(sequence: list, target: int) -> int:
     """A pure Python implementation of a linear search algorithm
 
-    :param sequence: a collection with comparable items (as sorted items not required
-        in Linear Search)
+    :param sequence: a collection with comparable items (sorting is not required for
+        linear search)
     :param target: item value to search
     :return: index of found item or -1 if item is not found
 

sorts/bogo_sort.py

@@ -16,7 +16,7 @@
 import random
 
 
-def bogo_sort(collection):
+def bogo_sort(collection: list) -> list:
     """Pure implementation of the bogosort algorithm in Python
     :param collection: some mutable ordered collection with heterogeneous
     comparable items inside
@@ -30,7 +30,7 @@ def bogo_sort(collection):
     [-45, -5, -2]
     """
 
-    def is_sorted(collection):
+    def is_sorted(collection: list) -> bool:
         for i in range(len(collection) - 1):
             if collection[i] > collection[i + 1]:
                 return False

sorts/bubble_sort.py

@@ -6,7 +6,7 @@ def bubble_sort_iterative(collection: list[Any]) -> list[Any]:
 
     :param collection: some mutable ordered collection with heterogeneous
     comparable items inside
-    :return: the same collection ordered by ascending
+    :return: the same collection ordered in ascending order
 
     Examples:
     >>> bubble_sort_iterative([0, 5, 2, 3, 2])
@@ -17,6 +17,12 @@ def bubble_sort_iterative(collection: list[Any]) -> list[Any]:
     [-45, -5, -2]
     >>> bubble_sort_iterative([-23, 0, 6, -4, 34])
     [-23, -4, 0, 6, 34]
+    >>> bubble_sort_iterative([1, 2, 3, 4])
+    [1, 2, 3, 4]
+    >>> bubble_sort_iterative([3, 3, 3, 3])
+    [3, 3, 3, 3]
+    >>> bubble_sort_iterative([56])
+    [56]
     >>> bubble_sort_iterative([0, 5, 2, 3, 2]) == sorted([0, 5, 2, 3, 2])
     True
     >>> bubble_sort_iterative([]) == sorted([])