Find Longest Substring Without Repeating Characters in Python

January 5, 2025

Given a string S, find the longest substring without repeating characters. If there are multiple such substrings with the same maximum length, return the first one encountered from the left.

Example
Input: "wobgrovw"

Output: "bgrovw"

Length: 6

Code


def lengthOfLongestSubstring(s: str):
    string = ""
    length = 0

    for c in s:
        if c in string:
            str_len = len(string)
            if length < str_len:
                length = str_len
            string = string.split(c)[1]+c
        else:
            string += c            
    
    str_len = len(string)
    if length < str_len:
        length = str_len
    
    print(string)
    return length

s = "wobgrovw"
print(lengthOfLongestSubstring(s))

>Solution :

Try This :

def lengthOfLongestSubstring(s: str):
    current_substring = ""
    longest_substring = ""
    max_length = 0

    for c in s:
        if c in current_substring:
            current_substring = current_substring.split(c, 1)[1] + c
        else:
            current_substring += c

        if len(current_substring) > max_length:
            max_length = len(current_substring)
            longest_substring = current_substring

    print(longest_substring)
    return max_length 

s = "wobgrovw"
print(lengthOfLongestSubstring(s))