This is python program for finding len of longest substring in given argument with no duplicates Leetcode 3

Will share optimized version later

Longest substring without repeating characters

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        # will post best version on https://www.computerscienceai.com
        
        #print = lambda *args , **kwargs : None
        l = {}; ls = 0; 

        #s = "123412345!@#" ; 
        li = 0 # this is last changed index  
        for i , ch in enumerate(s):
            if ch in l:
                #print(f"{ch} in l")
                # longest substring is 
                # earlier attempt 
                new_len =    i - 1 - li if ls != 0 else i   
                if new_len > ls :
                    #print(f"len is greater , new length { i - 1 - li  }")
                    ls = new_len 
                #print("Before clearning : " , l)
                # here we can drop keys which are earlier than i but doing so will hur performance so we will join it later
                li = l.pop(ch ) # none is danger 
                l[ch] = i 
                #print("Current char is added")
                #print("After clearing : " , l)
            else:
                l[ch] = i ; 
                #print(l)
        #print( l ) ; print ( li  )
        # check once if we have longest substring now
        l = { ch : 0 for ch , v in l.items() if v >= li }
        if ls < len(l):
            ls = len( l )
        # that is it boy 
        return ls

Output: