3. Longest Substring Without Repeating Characters(无重复字符的最长子串)

问题描述

英文

Given a string, find the length of the longest substring without repeating characters.

Example 1:

Input: "abcabcbb"
Output: 3 
Explanation: The answer is "abc", with the length of 3. 

Example 2:

Input: "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: "pwwkew"
Output: 3

Explanation: 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.

中文

给定一个字符串，请你找出其中不含有重复字符的 最长子串 的长度。

示例 1:

输入: "abcabcbb"
输出: 3 
解释: 因为无重复字符的最长子串是 "abc"，所以其长度为 3。

示例 2:

输入: "bbbbb"
输出: 1
解释: 因为无重复字符的最长子串是 "b"，所以其长度为 1。

示例 3:

输入: "pwwkew"
输出: 3
解释: 因为无重复字符的最长子串是 "wke"，所以其长度为 3。
     请注意，你的答案必须是 子串 的长度，"pwke" 是一个子序列，不是子串。

Solution

Python

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        max_len = 0
        tmp_str = ""
        for i in s:
            if i not in tmp_str:
                tmp_str = tmp_str + i
                tmp_len = len(tmp_str)
                if tmp_len > max_len:
                    max_len = tmp_len
            else:
                tmp_str = tmp_str[tmp_str.index(i)+1:]+i
        return max_len

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