(string)
return max_length
Find the length of the longest substring
    without repeating characters.
Find the length of the longest substring
    without repeating characters.
Find the length of the longest substring without repeating characters .
def longest_non_repeat_v1(string):
    """
    Find the length of the longest substring
    without repeating characters.
    """
    if string is None:
        return 0
    dict = {}
    max_length = 0
    j = 0
    for i in range(len(string)):
        if string[i] in dict:
            j = max(dict[string[i]], j)
        dict[string[i]] = i + 1
        max_length = max(max_length, i - j + 1)
    return max_length
def longest_non_repeat_v1 ( string ) : if string is None : return 0 dict = { } max_length = 0 j = 0 for i in range ( len ( string ) ) : if string [ i ] in dict : j = max ( dict [ string [ i ] ] , j ) dict [ string [ i ] ] = i + 1 max_length = max ( max_length , i - j + 1 ) return max_length