sock_merchant.py: Matching socks by color (#5761)

* Python file for finding number of pairs

* updating DIRECTORY.md

* fixed iterative_pair.py

* further fixed with type casting

* fixed naming conventions

* further fixed with naming convention

* documented done

* build issue fixed

* updating DIRECTORY.md

* Revert "documented done"

This reverts commit 3be15ca374f3ea3f01f725912dba59b939b058b5.

* Update canny.py

* Update test_digital_image_processing.py

* Update sobel_filter.py

* requirements.txt fixed

* keras<2.7.0

* Update sock_merchant.py

* doctest with black fixed

* Update sock_merchant.py
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: NChristian Clauss <cclauss@me.com>

DIRECTORY.md

@@ -39,6 +39,7 @@
   * [Binary Xor Operator](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/binary_xor_operator.py)
   * [Count 1S Brian Kernighan Method](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/count_1s_brian_kernighan_method.py)
   * [Count Number Of One Bits](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/count_number_of_one_bits.py)
+  * [Gray Code Sequence](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/gray_code_sequence.py)
   * [Reverse Bits](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/reverse_bits.py)
   * [Single Bit Manipulation Operations](https://github.com/TheAlgorithms/Python/blob/master/bit_manipulation/single_bit_manipulation_operations.py)
 
@@ -63,7 +64,7 @@
   * [Baconian Cipher](https://github.com/TheAlgorithms/Python/blob/master/ciphers/baconian_cipher.py)
   * [Base16](https://github.com/TheAlgorithms/Python/blob/master/ciphers/base16.py)
   * [Base32](https://github.com/TheAlgorithms/Python/blob/master/ciphers/base32.py)
-  * [Base64 Encoding](https://github.com/TheAlgorithms/Python/blob/master/ciphers/base64_encoding.py)
+  * [Base64](https://github.com/TheAlgorithms/Python/blob/master/ciphers/base64.py)
   * [Base85](https://github.com/TheAlgorithms/Python/blob/master/ciphers/base85.py)
   * [Beaufort Cipher](https://github.com/TheAlgorithms/Python/blob/master/ciphers/beaufort_cipher.py)
   * [Bifid](https://github.com/TheAlgorithms/Python/blob/master/ciphers/bifid.py)
@@ -219,6 +220,7 @@
   * Filters
     * [Bilateral Filter](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/bilateral_filter.py)
     * [Convolve](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/convolve.py)
+    * [Gabor Filter](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/gabor_filter.py)
     * [Gaussian Filter](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/gaussian_filter.py)
     * [Median Filter](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/median_filter.py)
     * [Sobel Filter](https://github.com/TheAlgorithms/Python/blob/master/digital_image_processing/filters/sobel_filter.py)
@@ -511,6 +513,7 @@
   * [Modular Exponential](https://github.com/TheAlgorithms/Python/blob/master/maths/modular_exponential.py)
   * [Monte Carlo](https://github.com/TheAlgorithms/Python/blob/master/maths/monte_carlo.py)
   * [Monte Carlo Dice](https://github.com/TheAlgorithms/Python/blob/master/maths/monte_carlo_dice.py)
+  * [Nevilles Method](https://github.com/TheAlgorithms/Python/blob/master/maths/nevilles_method.py)
   * [Newton Raphson](https://github.com/TheAlgorithms/Python/blob/master/maths/newton_raphson.py)
   * [Number Of Digits](https://github.com/TheAlgorithms/Python/blob/master/maths/number_of_digits.py)
   * [Numerical Integration](https://github.com/TheAlgorithms/Python/blob/master/maths/numerical_integration.py)
@@ -546,6 +549,7 @@
   * [Sieve Of Eratosthenes](https://github.com/TheAlgorithms/Python/blob/master/maths/sieve_of_eratosthenes.py)
   * [Sigmoid](https://github.com/TheAlgorithms/Python/blob/master/maths/sigmoid.py)
   * [Simpson Rule](https://github.com/TheAlgorithms/Python/blob/master/maths/simpson_rule.py)
+  * [Sock Merchant](https://github.com/TheAlgorithms/Python/blob/master/maths/sock_merchant.py)
   * [Softmax](https://github.com/TheAlgorithms/Python/blob/master/maths/softmax.py)
   * [Square Root](https://github.com/TheAlgorithms/Python/blob/master/maths/square_root.py)
   * [Sum Of Arithmetic Series](https://github.com/TheAlgorithms/Python/blob/master/maths/sum_of_arithmetic_series.py)

maths/sock_merchant.py

+from collections import Counter
+
+
+def sock_merchant(colors: list[int]) -> int:
+    """
+    >>> sock_merchant([10, 20, 20, 10, 10, 30, 50, 10, 20])
+    3
+    >>> sock_merchant([1, 1, 3, 3])
+    2
+    """
+    return sum(socks_by_color // 2 for socks_by_color in Counter(colors).values())
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
+
+    colors = [int(x) for x in input("Enter socks by color :").rstrip().split()]
+    print(f"sock_merchant({colors}) = {sock_merchant(colors)}")

requirements.txt

 beautifulsoup4
 fake_useragent
-keras
+keras<2.7.0
 lxml
 matplotlib
 numpy