Longest Unique Substring

Problem

Return the length of the longest substring of s that contains no repeated characters.

Use a sliding window with a dictionary storing each character's last index; when a repeat falls inside the current window, move the window start to just past the previous occurrence. Return 0 for the empty string.

Hint

Only move the start forward when the previous occurrence is still inside the window.

Test cases

case 1

in: ["abcabcbb"]

expected: 3

case 2

in: ["bbbbb"]

expected: 1

case 3

in: [""]

expected: 0

case 4

in: ["pwwkew"]

expected: 3

case 5

in: ["dvdf"]

expected: 3

Starter codePython

def length_of_longest_unique_substring(s):
    # Your code here
    pass

5 test cases · run your code against them in the editor