3. Longest Substring Without Repeating Characters

class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        n = len(s)
        table = {}
        imin = -1
        imax = 0
        res = 0
        for i,c in enumerate(s):
            if c in table:
                imin = max(imin, table[c])
                table[c] = i
                res = max(res, i - imin)
            else:
                table[c] = i
                # res = max(res, i - imin)
        res = max(res, n - 1 - imin)
        return res

主要的疏忽在于 最近的重复指针的更新。