1. 3. Longest Substring Without Repeating Characters(最长不重复子串)
class Solution:
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
if len(s) == 0:
return 0
max_len = 0
pre_index = {}
start_index = 0
for i in range(0, len(s)):
# 如果当前字符为重复，并且start_index 比当前字符上一次出现的位置靠左或相同，更新start_index 到上一次右侧
if (s[i] in pre_index.keys()) and (start_index <= pre_index[s[i]]):
start_index = pre_index[s[i]]+1
# 没有出现重复，则计算当前最大长度
else:
max_len = max(max_len, i-start_index+1)
pre_index[s[i]] = i
return max_len
