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

原创

Limer123 2022-12-07 05:22:16 ©著作权

文章标签 LeetCode OJ C++ 字符串 bc 文章分类 后端开发

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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