LeetCode 3 : Longest Substring Without Repeating Characters ---- 不重复的子串

原题链接： https://leetcode.com/problems/longest-substring-without-repeating-characters/
一：原题内容

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 asubstring,

"pwke"

is a
subsequence and not a substring.

二：AC代码

class Solution
{
public:
int lengthOfLongestSubstring(string s)
{
int flag[128]={0};
int ans=0;//the answer
int j=0;

for(int i=0;i<s.size();i++)
{
if(flag[s[i]]>0)
{
j=max(j,flag[s[i]]);
}

flag[s[i]]=i+1;
ans=max(ans,i-j+1);
}

return ans;
}
};

class Solution(object):
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""

ret=0
left=0
d={}

for index,value in enumerate(s):
if value in d and d[value]>=left:
left=d[value]+1

d[value]=index
ret=max(ret,index-left+1)
return ret

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