Given a string s, find the length of the longest substring without repeating characters.
The idea is checking whenever we find any letter which is repeating we can find previous position and find the difference
we can check "repeating" by maintain hash functions like map
Given a string s, find the length of the longest substring without repeating characters. The idea is checking whenever we find any letter which is repeating we can find previous position and find the difference we can check "repeating" by maintain hash functions like map