LeetCode Q003 Longest Substring

Q003 Longest Substring



 a b c a b c b b
   |   |
 | i   cursor
 start

We need 3 pointers, use sliding window [i, cursor] to check if there is any repeating element
 Once found repeating element, update max length could be found within the sliding window,
 and move start to the element next to the repeated element.
 Then start the next round of sliding window

Example solution

https://github.com/Sylvia-YiyinShen/Algorithm/blob/master/SlidingWindow/Q003LongestSubstring.playground/Contents.swift