Solution to https://leetcode.com/problems/longest-substring-without-repeating-characters/

gistfile1.txt

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        max_run_length = 0
        start_run_index = -1
        while start_run_index <= len(s) - max_run_length:
            start_run_index += 1
            run_letters = set([]) if start_run_index == 0 else set(list(s[start_run_index:start_run_index+max_run_length]))
            if len(run_letters) < max_run_length:
                continue
            for k in s[start_run_index+max_run_length:]:
                if k in run_letters:
                    break
                run_letters.add(k)
                max_run_length += 1
        return max_run_length

    def lengthOfLongestSubstring(self, s: str) -> int:
        seenDict = {}
        maxCount = 0
        lastLegalIndex = 0

        for index, letter in enumerate(s):
            if letter in seenDict:
                lastLegalIndex = max(seenDict[letter]+1,lastLegalIndex)
            seenDict[letter] = index
            maxCount = max(maxCount, index - lastLegalIndex+1)
        return maxCount```

@jkamashian yours is a lot more clever than mine!

@syedsaqibali but you have no idea how long this took me 🤣