#
# @lc app=leetcode.cn id=3 lang=python3
#
# [3] 无重复字符的最长子串
#

# @lc code=start
class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        rtn_vle = 0
        chlid_str = ''
        child_str_map = dict()
        # target_str = dict()
        # Judge whether s is legle
        if s:
            # Set initial value
            strt_num = 0
            chlid_str = s[0]
            child_str_map[s[0]] = 0
            last_vle_flg = False
            # Use slide window to calculate target string
            for tp_i,tp_str in enumerate(s):
                if (tp_i + 1) == len(s):
                    last_vle_flg = True
                # tp_str not in child_str 
                if (tp_str not in chlid_str) and \
                    tp_i > 0:
                    chlid_str = chlid_str + tp_str
                    # Judge last value
                    if last_vle_flg:
                        # target_str[chlid_str] = len(chlid_str)
                        if len(chlid_str) > rtn_vle:
                            rtn_vle = len(chlid_str)
                elif tp_i > 0:
                    # target_str[chlid_str] = len(chlid_str)
                    if len(chlid_str) > rtn_vle:
                        rtn_vle = len(chlid_str)
                    strt_num = child_str_map[tp_str] + 1
                    chlid_str = s[strt_num:(tp_i+1)]
                else:
                    # target_str[chlid_str] = 1
                    rtn_vle = 1
                # Refresh child string map value
                child_str_map[s[tp_i]] = tp_i
        # Calculate return
        return rtn_vle

# Test code
Test = Solution()
print(Test.lengthOfLongestSubstring(' '))


# @lc code=end