Ading Array Addition solution

Author: rlishtaba

README.md

@@ -465,6 +465,10 @@ Solutions to various challenges published at www.hackerrank.com
 * Binary Search Tree LCA
 * Shortest Path in Unweighted Graph with cycles
 * Weighted Path
+* PowerSet
+* Subset Sum
+* Two Sum
+* Array Addition
 
 ## Contributing
 

py_algorithms/challenges/coderbyte/array_addition.py

@@ -0,0 +1,24 @@
+from typing import List
+
+
+class ArrayAddition:
+    def __call__(self, arr: List[int]) -> bool:
+        max_num = max(arr)
+        arr.remove(max_num)
+        return self._test(arr, max_num)
+
+    @classmethod
+    def _test(cls, arr: List[int], max_num: int) -> bool:
+        for x in arr:
+            # Found, return early
+            if x == max_num:
+                return True
+            # clone current list
+            c_arr = list(arr)
+            # remove used number
+            c_arr.remove(x)
+            # recur test, for target - removed value
+            if cls._test(c_arr, max_num - x):
+                return True
+        # Target not found
+        return False

tests/py_algorithms/challenges/coderbyte/array_addition_test.py

@@ -0,0 +1,12 @@
+from py_algorithms.challenges.coderbyte.array_addition import ArrayAddition
+
+
+class ArrayAdditionTest:
+    def test_impl(self):
+        inputs = {
+            True: [4, 6, 23, 10, 1, 3],
+            False: [4, 6, 123, 10, 1, 3]
+        }
+        f = ArrayAddition()
+        for key in inputs:
+            assert f(inputs[key]) == key