3. Longest Substring Without Repeating Characters

Description:

Solution:

 

We use set() for substring. (Sliding Window)

In example 1, the string is abcabcbb.

We are gonna store substring until meet duplicated character.

abc -> now we meet "a"

Remove the first "a", now new substring is bca.

The length of substring should be r - l + 1.

 

Time Complexity: O(n)

Space Complexity: O(n)