Longest Substring Without Repeating Characters

Given a string 'S' of length 'L', return the length of the longest substring without repeating characters.

Example:

Suppose given input is "abacb", then the length of the longest substring without repeating characters will be 3 ("acb").

Input Format:

Each input contains a single line which contains the string 'S', Where 'S' denotes the input string containing english letters ( both UpperCase and LowerCase), digits, symbols, and spaces.

Output Format:

Print a single integer denoting the length of the longest substring without repeating characters.

Note:

You do not need to print anything, it has already been taken care of. Just implement the given function.

Constraints:

0 <= L <= 10^5     

Time limit: 1 sec

Follow Up:

Can you solve this problem in O(L) time and space complexity?