Python program to check if a string contains all unique characters
To implement an algorithm to determine if a string contains all unique characters.
Examples:
Input : s = “abcd”
Output: True
“abcd” doesn’t contain any duplicates. Hence the output is True.
Input : s = “abbd”
Output: False
“abbd” contains duplicates. Hence the output is False.
One solution is to create an array of boolean values, where the flag at the index i indicates whether character i in the alphabet is contained in the string. The second time you see this character you can immediately return false.
You can also return false if the string length exceeds the number of unique characters in the alphabet.
def isUniqueChars(st): # String length cannot be more than # 256. if len(st) > 256: return False # Initialize occurrences of all characters char_set = [False] * 128 # For every character, check if it exists # in char_set for i in range(0, len(st)): # Find ASCII value and check if it # exists in set. val = ord(st[i]) if char_set[val]: return False char_set[val] = True return True # driver code st = "abcd"print(isUniqueChars(st)) |
chevron_right
filter_none
Output:
True
Recommended Posts:
- Efficiently check if a string has all unique characters without using any additional data structure
- Program to check if first and the last characters of string are equal
- Minimum deletions from string to reduce it to string with at most 2 unique characters
- Python | Check if frequencies of all characters of a string are different
- Python | Ways to check string contain all same characters
- Check if both halves of the string have same set of characters in Python
- Determine if a string has all Unique Characters
- String with maximum number of unique characters
- Minimize number of unique characters in string
- Find the longest substring with k unique characters in a given string
- Python program to check if a given string is Keyword or not
- Python program to check if given string is pangram
- Python program to check if a string is palindrome or not
- Python program to check if given string is vowel Palindrome
- Check if an encoding represents a unique binary string
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
