solution for string rotation and zero matrix python

Author: nickolasteixeira

Python/chapter01/1.8 - Zero Matrix/Nick.py

@@ -0,0 +1,35 @@
+#!/usr/bin/python3
+import random
+
+
+def build_matrix(w, h, max=10):
+    '''function that builds a matrix with random numbers including 0'''
+    return [[random.randint(0, max) for _ in range(w)] for _ in range(h)]
+
+
+def zero_matrix(matrix):
+    '''Write an algorithm such that if an element in an MxN matrix is 0, its entire row and
+column are set to 0.'''
+    row, column = [], []
+    zero_present = False
+
+    for idx1 in range(len(matrix)):
+        for idx2 in range(len(matrix[idx1])):
+            if matrix[idx1][idx2] is 0:
+                zero_present = True
+                row.append(idx1)
+                column.append(idx2)
+
+    if zero_present:
+        for idx1 in range(len(matrix)):
+            for idx2 in range(len(matrix[idx1])):
+                if idx1 in row:
+                    matrix[idx1][idx2] = 0
+                if idx2 in column:
+                    matrix[idx1][idx2] = 0
+
+if __name__ == '__main__':
+    matrix = build_matrix(4, 4)
+    print("Old Matrix => ", matrix)
+    zero_matrix(matrix)
+    print("New Matrix => ", matrix)

Python/chapter01/1.9 - String Rotation/Nick.py

@@ -0,0 +1,21 @@
+#!/usr/bin/python3
+import unittest
+
+def is_rotation(s1, s2):
+    '''Assumeyou have a method isSubstringwhich checks if oneword is a substring
+of another. Given two strings, sl and s2, write code to check if s2 is a rotation of sl using only one
+call to isSubstring (e.g., "waterbottle" is a rotation of"erbottlewat"). '''
+    if len(s1) is len(s2) and len(s1) > 0:
+        return s2 in s1 + s1
+    return False
+
+
+class Test(unittest.TestCase):
+    def test1(self):
+        self.assertTrue(is_rotation('waterbottle', 'erbottlewat'))
+        self.assertFalse(is_rotation('watermellon', 'watermellons'))
+        self.assertFalse(is_rotation('waterbottle', 'bottleaterw'))
+
+
+if __name__ == '__main__':
+    unittest.main()