(python)leetcode刷题笔记03 Longest Substring Without Repeating Characters

3. Longest Substring Without Repeating Characters

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

ANSWER:

class Solution:
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        if s:
            i=0
            max_sub =s[0]
            len_s=len(s)
            while i<len(s):
                j=i+1
                for index in range(j,len_s):
                    if s[index] not in s[i:index]:
                        if len(s[i:index+1])>len(max_sub):
                            max_sub=s[i:index+1]
                    else:
                        break
                i+=1
            return len(max_sub)
        else:
            return 0

def main(s):
    if s:
        i=0
        max_sub =s[0]
        len_s=len(s)
        while i<len(s):
            j=i+1
            for index in range(j,len_s):
                if s[index] not in s[i:index]:
                    if len(s[i:index+1])>len(max_sub):
                        max_sub=s[i:index+1]
                else:
                    break
            i+=1
        return len(max_sub)
    else:
        return 0
if __name__ == '__main__':
    s='pwwke'
    print(main(s))