Add Python function to check Disarium numbers (#13603)

* Add Python function to check Disarium numbers

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* updating DIRECTORY.md

* Add documentation link for Disarium number check

Added a link to Rosetta Code for Disarium numbers.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
Co-authored-by: cclauss <cclauss@users.noreply.github.com>

Author: 3 people

DIRECTORY.md

@@ -760,6 +760,7 @@
   * [Decimal To Fraction](maths/decimal_to_fraction.py)
   * [Derangement](maths/derangement.py)
   * [Digital Root](maths/digital_root.py)
+  * [Disarium](maths/disarium.py)
   * [Dodecahedron](maths/dodecahedron.py)
   * [Double Factorial](maths/double_factorial.py)
   * [Dual Number Automatic Differentiation](maths/dual_number_automatic_differentiation.py)

maths/disarium.py

@@ -0,0 +1,24 @@
+def is_disarium(num: int) -> bool:
+    """
+    Check if a number is Disarium.
+
+    https://rosettacode.org/wiki/Disarium_numbers
+
+    >>> is_disarium(89)
+    True
+    >>> is_disarium(75)
+    False
+    >>> is_disarium(135)
+    True
+    """
+    digits = list(str(num))
+    total = 0
+    for i in range(len(digits)):
+        total += int(digits[i]) ** (i + 1)
+    return total == num
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod(verbose=True)