Cracking the Coding Interview, 6th Ed., Chapter 1 Question 1: Is Unique - naive python solution

ch101-is_unique-naive.py

# naive solution
# complexity:
# time - O(n^2)
# space - O(1)

def naive_is_unique(input_string):
    length = len(input_string)

    if length < 2:
        return True

    for i, c in enumerate(input_string):
        if i == length - 1:
            break
        for j in range(i+1, length):
            if input_string[j] == c:
                return False
    return True