leetcode3 Longest Substring Without Repeating Characters【Python刷题】【哈希】
Given a string, find the length of the longest substring without repeating characters.
Examples:
Given "abcabcbb", the answer is "abc", which the length is 3.
Given "bbbbb", the answer is "b", with the length of 1.
Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.
问最长无重复字符的子串
想到记录这钱这个重复字符出现的位置
注意是字符，没说是小写字母，WA了一发
注意st和上次出现位置的前后顺序，要是上次出现位置在st之前就不用更新了，又WA了一发
吐槽py不能用字符直接减
class Solution(object):
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
pos=[]
for i in range(200):
pos.append(-1)
mlen=0
st=0
for i in range(len(s)):
if(pos[ord(s[i])]<>-1 and pos[ord(s[i])]>=st):
st=pos[ord(s[i])]+1
pos[ord(s[i])]=i
mlen=max(mlen,i-st+1)
return mlen
