Merge pull request #1398 from ivan1016017/september18

adding algo

Author: ivanpenaloza

src/my_project/interviews/top_150_questions_round_19/pow_x_n.py

@@ -0,0 +1,14 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def myPow(self, x, n):
+
+        if not n: 
+            return 1
+        if n < 1: 
+            return self.myPow(1/x, -n)
+        if n % 2: 
+            return x*self.myPow(x,n-1)
+        else: 
+            return self.myPow(x**2,n//2)

tests/test_150_questions_round_19/tets_pow_x_n_round_19.py

@@ -0,0 +1,29 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_19\
+.pow_x_n import Solution
+
+class PowxnTestCase(unittest.TestCase):
+
+    def test_powxn_zero_power(self):
+        solution = Solution()
+        output = solution.myPow(x=2, n=0) 
+        target = 1
+        self.assertEqual(output, target)
+
+    def test_powxn_negative_power(self):
+        solution = Solution()
+        output = solution.myPow(x=2, n=-1) 
+        target = 0.5
+        self.assertEqual(output, target)
+
+    def test_powxn_odd_power(self):
+        solution = Solution()
+        output = solution.myPow(x=2, n=1) 
+        target = 2
+        self.assertEqual(output, target) 
+
+    def test_powxn_even_power(self):
+        solution = Solution()
+        output = solution.myPow(x=2, n=2) 
+        target = 4
+        self.assertEqual(output, target)