Add butterfly pattern implementation (TheAlgorithms#12493)

* Add butterfly pattern implementation

* Add butterfly pattern implementation

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

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* Add finalized butterfly pattern implementation and test

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

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

* Delete graphics/test_butterfly_pattern.py

* Update butterfly_pattern.py

* Update butterfly_pattern.py

* Update butterfly_pattern.py

* Update butterfly_pattern.py

* Update butterfly_pattern.py

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Maxim Smolskiy <mithridatus@mail.ru>

graphics/butterfly_pattern.py

@@ -0,0 +1,46 @@
+def butterfly_pattern(n: int) -> str:
+    """
+    Creates a butterfly pattern of size n and returns it as a string.
+
+    >>> print(butterfly_pattern(3))
+    *   *
+    ** **
+    *****
+    ** **
+    *   *
+    >>> print(butterfly_pattern(5))
+    *       *
+    **     **
+    ***   ***
+    **** ****
+    *********
+    **** ****
+    ***   ***
+    **     **
+    *       *
+    """
+    result = []
+
+    # Upper part
+    for i in range(1, n):
+        left_stars = "*" * i
+        spaces = " " * (2 * (n - i) - 1)
+        right_stars = "*" * i
+        result.append(left_stars + spaces + right_stars)
+
+    # Middle part
+    result.append("*" * (2 * n - 1))
+
+    # Lower part
+    for i in range(n - 1, 0, -1):
+        left_stars = "*" * i
+        spaces = " " * (2 * (n - i) - 1)
+        right_stars = "*" * i
+        result.append(left_stars + spaces + right_stars)
+
+    return "\n".join(result)
+
+
+if __name__ == "__main__":
+    n = int(input("Enter the size of the butterfly pattern: "))
+    print(butterfly_pattern(n))