Created combination.py in maths (keon#304)

geon0325 · goswami-rahul · commit bb9d6c195665 · 2018-06-04T17:07:07.000+05:30
* Create combination.py

* Update __init__.py

* Update test_maths.py

* Update README.md

* Update README_CN.md

* Update README_GE.md

* Update README_JP.md

* Update README_KR.md
diff --git a/README.md b/README.md
@@ -172,6 +172,7 @@ If you want to uninstall algorithms, it is as simple as:
     - [valid_sudoku](algorithms/map/valid_sudoku.py)
 - [maths](algorithms/maths)
     - [base_conversion](algorithms/maths/base_conversion.py)
+    - [combination](algorithms/maths/combination.py)
     - [extended_gcd](algorithms/maths/extended_gcd.py)
     - [gcd/lcm](algorithms/maths/gcd.py)
     - [generate_strobogrammtic](algorithms/maths/generate_strobogrammtic.py)
diff --git a/README_CN.md b/README_CN.md
@@ -164,6 +164,7 @@ pip3 uninstall -y algorithms
     - [valid_sudoku：有效数独](algorithms/map/valid_sudoku.py)
 - [math：数学问题](algorithms/maths)
     - [extended_gcd：扩展欧几里得算法](algorithms/maths/extended_gcd.py)
+    - [combination](algorithms/maths/combination.py)
     - [gcd/lcm：最大公约数和最小公倍数](algorithms/maths/gcd.py)
     - [prime_test：主要测试](algorithms/maths/prime_test.py)
     - [primes_sieve_of_eratosthenes：埃拉托色尼的质数筛](algorithms/maths/primes_sieve_of_eratosthenes.py)
diff --git a/README_GE.md b/README_GE.md
@@ -179,6 +179,7 @@ Um das Projekt zu deinstallieren tippen Sie folgendes:
     - [valid_sudoku](algorithms/map/valid_sudoku.py)
 - [maths](algorithms/maths)
     - [base_conversion](algorithms/maths/base_conversion.py)
+    - [combination](algorithms/maths/combination.py)
     - [extended_gcd](algorithms/maths/extended_gcd.py)
     - [gcd/lcm](algorithms/maths/gcd.py)
     - [generate_strobogrammtic](algorithms/maths/generate_strobogrammtic.py)
diff --git a/README_JP.md b/README_JP.md
@@ -1,6 +1,6 @@
 [English](README.md) | [简体中文](README_CN.md) | [Deutsch](README_GE.md) | 日本語 | [한국어](README_KR.md)
 
-pythonのデータ構造とアルゴリズム
+Pythonのデータ構造とアルゴリズム
 =========================================
 
 Python 3で開発された簡単で明確なデータ構造とアルゴリズムの例を紹介します。
@@ -169,6 +169,7 @@ if __name__ == "__main__":
     - [valid_sudoku](algorithms/map/valid_sudoku.py)
 - [maths : 数学](algorithms/maths)
     - [base_conversion](algorithms/maths/base_conversion.py)
+    - [combination](algorithms/maths/combination.py)
     - [extended_gcd](algorithms/maths/extended_gcd.py)
     - [gcd/lcm](algorithms/maths/gcd.py)
     - [generate_strobogrammtic](algorithms/maths/generate_strobogrammtic.py)
diff --git a/README_KR.md b/README_KR.md
@@ -165,6 +165,7 @@ if __name__ == "__main__":
     - [valid_sudoku](algorithms/map/valid_sudoku.py)
 - [maths : 수학 계산](algorithms/maths)
     - [base_conversion](algorithms/maths/base_conversion.py)
+    - [combination](algorithms/maths/combination.py)
     - [extended_gcd](algorithms/maths/extended_gcd.py)
     - [gcd/lcm](algorithms/maths/gcd.py)
     - [generate_strobogrammtic](algorithms/maths/generate_strobogrammtic.py)
diff --git a/algorithms/maths/__init__.py b/algorithms/maths/__init__.py
@@ -9,3 +9,4 @@
 from .pythagoras import *
 from .rabin_miller import *
 from .rsa import *
+from .combination import *
diff --git a/algorithms/maths/combination.py b/algorithms/maths/combination.py
@@ -0,0 +1,6 @@
+def combination(n, r):
+    # This function calculates nCr
+    if n == r or r == 0:
+        return 1
+    else:
+        return combination(n-1, r-1) + combination(n-1, r)
diff --git a/tests/test_maths.py b/tests/test_maths.py
@@ -9,7 +9,8 @@
     primes,
     pythagoras,
     is_prime,
-    encrypt, decrypt, generate_key
+    encrypt, decrypt, generate_key,
+    combination
 )
 
 import unittest
@@ -202,6 +203,17 @@ def test_encrypt_decrypt(self):
     #         dec = decrypt(en, d, n)
     #         self.assertEqual(data,dec)
 
+class TestCombination(unittest.TestCase):
+    """[summary]
+    Test for the file rsa.py
+
+    Arguments:
+        unittest {[type]} -- [description]
+    """
 
+    def test_combination(self):
+        self.assertEqual(10, combination(5, 2))
+        self.assertEqual(252, combination(10, 5))
+        
 if __name__ == "__main__":
     unittest.main()
