String

3. Longest Substring Without Repeating Characters

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        used = {}
        start = 0
        res = 0
        for i,c in enumerate(s):
            if c in used and used[c]>=start:
                start = used[c]+1
            else: 
                res=max(res, i-start+1)
            used[c] = i
        return res

763. Partition Labels

class Solution:
    def partitionLabels(self, S: str) -> List[int]:
        if not S:return []
        d = {}
        for i,c in enumerate(S):
            d[c] = i
        res, this_res = [], 0
        seen = set()
        for i, c in enumerate(S):
            this_res+=1
            if i==d[c]:
                seen.discard(c)
                if not seen:
                    res.append(this_res)
                    this_res = 0
            else:
                seen.add(c)
        return res