chore(Python): added is unique character algorithm (#428)

.gitignore

@@ -12,3 +12,5 @@ Thumbs.db
 *.class
 *.idea
 
+
+

algorithms/Python/README.md

@@ -54,6 +54,7 @@
 4. [Remove Duplicates from a String](strings/remove_duplicates_from_a_string.py)
 5. [First Non Repeating Character](strings/first_non_repeating_character.py)
 6. [Longest Common Subsequence](strings/longest_common_subsequence.py)
+7. [Unique Character](strings/unique_character.py)
 
 ## Dynamic Programming
 

algorithms/Python/strings/unique_character.py

@@ -0,0 +1,30 @@
+"""
+    Algorithm Type : Find the all the characters in the given strings are unique
+    Time Complexity:    O(n)
+"""
+s = 'abcd'
+
+def is_unique(s: str) -> bool:
+    """
+    >>> is_unique('ABCDE')
+    True
+    """
+    """
+    >>> is_unique('programmer')
+    False
+    """
+    
+    
+    arr = [False for _ in range(128)] #creating hashtable with False input
+    for character in s:        #iterate throughout the string
+        char_value = ord(character)
+        if arr[char_value]:
+            return False
+        else:
+            arr[char_value] = True
+    return True
+    
+if __name__ == "__main__": 
+    print(is_unique(s))
+    print(is_unique('ABCDEDD'))
+    print(is_unique('programmer'))