3 unique strings algos

Author: nickolasteixeira

Python/chapter01/1.1 - Is Unique/Nick1.py

@@ -0,0 +1,67 @@
+#!/usr/bin/python3
+'''
+Module that implements an algorithm to determine if a string has all unique characters. What if you
+cannot use additional data structures?
+'''
+
+import unittest
+
+def unique(string):
+    '''checks if string input is unique
+    Args:
+        string (str): string to check
+    '''
+    return len(set(string)) is len(string)
+
+def unique2(string):
+    '''checks if string input is unique
+    args:
+        string (str): string to check
+    '''
+    letters = {}
+    for letter in string:
+        letters[letter] = letters.get(letter, 0) + 1
+        if letters.get(letter) is not None and letters[letter] > 1:
+                return False
+    return True
+
+def unique3(string):
+    '''checks if string input is unique, no new data structures
+    args:
+        string (str): string to check
+    '''
+    new_string = sorted(string)
+    for idx in range(len(new_string) - 1):
+        if new_string[idx] == new_string[idx + 1]:
+            return False
+
+    return True
+
+
+class Test(unittest.TestCase):
+    def test1(self):
+        all_true = ["Nick", "world"]
+        all_false = ["eee", "hello"]
+
+        for idx in range(len(all_true)):
+            self.assertTrue(unique(all_true[idx]))
+            self.assertFalse(unique(all_false[idx]))
+
+    def test2(self):
+        all_true = ["Nick", "world", "Sue", "John", "abcdefghijklmnopqrstuvwxyz"]
+        all_false = ["eee", "hello", "nicki", "johnny", "suuu"]
+
+        for idx in range(len(all_true)):
+            self.assertTrue(unique2(all_true[idx]))
+            self.assertFalse(unique2(all_false[idx]))
+
+    def test3(self):
+        all_true = ["Nick", "world", "Sue", "John", "abcdefghijklmnopqrstuvwxyz"]
+        all_false = ["eee", "hello", "nicki", "johnny", "suuu"]
+
+        for idx in range(len(all_true)):
+            self.assertTrue(unique3(all_true[idx]))
+            self.assertFalse(unique3(all_false[idx]))
+
+if __name__ == '__main__':
+    unittest.main()