Merge branch 'master' into master

Marioman2023 · web-flow · commit 87c8c908d4f6 · 2026-03-16T09:33:43.000+13:00
diff --git a/CONTRIBUTING.md b/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:
diff --git a/DIRECTORY.md b/DIRECTORY.md
@@ -469,6 +469,11 @@
 
 ## Geometry
   * [Geometry](geometry/geometry.py)
+  * [Graham Scan](geometry/graham_scan.py)
+  * [Jarvis March](geometry/jarvis_march.py)
+  * Tests
+    * [Test Graham Scan](geometry/tests/test_graham_scan.py)
+    * [Test Jarvis March](geometry/tests/test_jarvis_march.py)
 
 ## Graphics
   * [Bezier Curve](graphics/bezier_curve.py)
@@ -981,6 +986,7 @@
     * [Sol2](project_euler/problem_014/sol2.py)
   * Problem 015
     * [Sol1](project_euler/problem_015/sol1.py)
+    * [Sol2](project_euler/problem_015/sol2.py)
   * Problem 016
     * [Sol1](project_euler/problem_016/sol1.py)
     * [Sol2](project_euler/problem_016/sol2.py)
diff --git a/backtracking/coloring.py b/backtracking/coloring.py
@@ -104,6 +104,14 @@ def color(graph: list[list[int]], max_colors: int) -> list[int]:
     >>> max_colors = 2
     >>> color(graph, max_colors)
     []
+    >>> color([], 2)  # empty graph
+    []
+    >>> color([[0]], 1)  # single node, 1 color
+    [0]
+    >>> color([[0, 1], [1, 0]], 1)  # 2 nodes, 1 color (impossible)
+    []
+    >>> color([[0, 1], [1, 0]], 2)  # 2 nodes, 2 colors (possible)
+    [0, 1]
     """
     colored_vertices = [-1] * len(graph)
 
diff --git a/backtracking/generate_parentheses.py b/backtracking/generate_parentheses.py
@@ -64,6 +64,10 @@ def generate_parenthesis(n: int) -> list[str]:
     Example 2:
     >>> generate_parenthesis(1)
     ['()']
+
+    Example 3:
+    >>> generate_parenthesis(0)
+    ['']
     """
 
     result: list[str] = []
diff --git a/backtracking/generate_parentheses_iterative.py b/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))
diff --git a/backtracking/n_queens.py b/backtracking/n_queens.py
@@ -33,6 +33,14 @@ def is_safe(board: list[list[int]], row: int, column: int) -> bool:
     False
     >>> is_safe([[0, 0, 1], [0, 0, 0], [0, 0, 0]], 1, 1)
     False
+    >>> is_safe([[1, 0, 0], [0, 0, 0], [0, 0, 0]], 1, 2)
+    True
+    >>> is_safe([[1, 0, 0], [0, 0, 0], [0, 0, 0]], 2, 1)
+    True
+    >>> is_safe([[0, 0, 0], [1, 0, 0], [0, 0, 0]], 0, 2)
+    True
+    >>> is_safe([[0, 0, 0], [1, 0, 0], [0, 0, 0]], 2, 2)
+    True
     """
 
     n = len(board)  # Size of the board
diff --git a/backtracking/word_break.py b/backtracking/word_break.py
@@ -66,6 +66,9 @@ def word_break(input_string: str, word_dict: set[str]) -> bool:
 
     >>> word_break("catsandog", {"cats", "dog", "sand", "and", "cat"})
     False
+
+    >>> word_break("applepenapple", {})
+    False
     """
 
     return backtrack(input_string, word_dict, 0)
diff --git a/geodesy/lamberts_ellipsoidal_distance.py b/geodesy/lamberts_ellipsoidal_distance.py
@@ -32,6 +32,26 @@ def lamberts_ellipsoidal_distance(
     Returns:
         geographical distance between two points in metres
 
+    >>> lamberts_ellipsoidal_distance(100, 0, 0, 0)
+    Traceback (most recent call last):
+    ...
+    ValueError: Latitude must be between -90 and 90 degrees
+
+    >>> lamberts_ellipsoidal_distance(0, 0, -100, 0)
+    Traceback (most recent call last):
+    ...
+    ValueError: Latitude must be between -90 and 90 degrees
+
+    >>> lamberts_ellipsoidal_distance(0, 200, 0, 0)
+    Traceback (most recent call last):
+    ...
+    ValueError: Longitude must be between -180 and 180 degrees
+
+    >>> lamberts_ellipsoidal_distance(0, 0, 0, -200)
+    Traceback (most recent call last):
+    ...
+    ValueError: Longitude must be between -180 and 180 degrees
+
     >>> from collections import namedtuple
     >>> point_2d = namedtuple("point_2d", "lat lon")
     >>> SAN_FRANCISCO = point_2d(37.774856, -122.424227)
@@ -46,6 +66,14 @@ def lamberts_ellipsoidal_distance(
     '9,737,326 meters'
     """
 
+    # Validate latitude values
+    if not -90 <= lat1 <= 90 or not -90 <= lat2 <= 90:
+        raise ValueError("Latitude must be between -90 and 90 degrees")
+
+    # Validate longitude values
+    if not -180 <= lon1 <= 180 or not -180 <= lon2 <= 180:
+        raise ValueError("Longitude must be between -180 and 180 degrees")
+
     # CONSTANTS per WGS84 https://en.wikipedia.org/wiki/World_Geodetic_System
     # Distance in metres(m)
     # Equation Parameters
diff --git a/maths/area.py b/maths/area.py
@@ -552,7 +552,6 @@ def area_reg_polygon(sides: int, length: float) -> float:
 length of a side"
         )
     return (sides * length**2) / (4 * tan(pi / sides))
-    return (sides * length**2) / (4 * tan(pi / sides))
 
 
 if __name__ == "__main__":
diff --git a/maths/factorial.py b/maths/factorial.py
@@ -41,21 +41,21 @@ def factorial_recursive(n: int) -> int:
     https://en.wikipedia.org/wiki/Factorial
 
     >>> import math
-    >>> all(factorial(i) == math.factorial(i) for i in range(20))
+    >>> all(factorial_recursive(i) == math.factorial(i) for i in range(20))
     True
-    >>> factorial(0.1)
+    >>> factorial_recursive(0.1)
     Traceback (most recent call last):
         ...
-    ValueError: factorial() only accepts integral values
-    >>> factorial(-1)
+    ValueError: factorial_recursive() only accepts integral values
+    >>> factorial_recursive(-1)
     Traceback (most recent call last):
         ...
-    ValueError: factorial() not defined for negative values
+    ValueError: factorial_recursive() not defined for negative values
     """
     if not isinstance(n, int):
-        raise ValueError("factorial() only accepts integral values")
+        raise ValueError("factorial_recursive() only accepts integral values")
     if n < 0:
-        raise ValueError("factorial() not defined for negative values")
+        raise ValueError("factorial_recursive() not defined for negative values")
     return 1 if n in {0, 1} else n * factorial_recursive(n - 1)
 
 
diff --git a/maths/fibonacci.py b/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
diff --git a/maths/greatest_common_divisor.py b/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
diff --git a/maths/matrix_exponentiation.py b/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()
 
diff --git a/maths/modular_division.py b/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
diff --git a/project_euler/problem_015/sol2.py b/project_euler/problem_015/sol2.py
@@ -0,0 +1,32 @@
+"""
+Problem 15: https://projecteuler.net/problem=15
+
+Starting in the top left corner of a 2x2 grid, and only being able to move to
+the right and down, there are exactly 6 routes to the bottom right corner.
+How many such routes are there through a 20x20 grid?
+"""
+
+
+def solution(n: int = 20) -> int:
+    """
+    Solve by explicitly counting the paths with dynamic programming.
+
+    >>> solution(6)
+    924
+    >>> solution(2)
+    6
+    >>> solution(1)
+    2
+    """
+
+    counts = [[1 for _ in range(n + 1)] for _ in range(n + 1)]
+
+    for i in range(1, n + 1):
+        for j in range(1, n + 1):
+            counts[i][j] = counts[i - 1][j] + counts[i][j - 1]
+
+    return counts[n][n]
+
+
+if __name__ == "__main__":
+    print(solution())
diff --git a/searches/binary_search.py b/searches/binary_search.py
diff --git a/searches/linear_search.py b/searches/linear_search.py
diff --git a/sorts/bogo_sort.py b/sorts/bogo_sort.py
diff --git a/sorts/bubble_sort.py b/sorts/bubble_sort.py
diff --git a/strings/count_vowels.py b/strings/count_vowels.py
diff --git a/strings/palindrome.py b/strings/palindrome.py
diff --git a/strings/reverse_letters.py b/strings/reverse_letters.py

Original file line number	Diff line number	Diff line change
`@@ -552,7 +552,6 @@ def area_reg_polygon(sides: int, length: float) -> float:`
`552`	`552`	`length of a side"`
`553`	`553`	`)`
`554`	`554`	`return (sides * length*2) / (4 tan(pi / sides))`
`555`		`- return (sides * length*2) / (4 tan(pi / sides))`
`556`	`555`
`557`	`556`
`558`	`557`	`if __name__ == "__main__":`