Summary of one question per day: linked list (continuously updated)

3. Longest substring without repeating characters Medium The sliding window 、 Hash table 2021/11/10

Given a string s , Please find out that there are no duplicate characters in it Longest substrings The length of .
Example ：
Input : s = “pwwkew”
Output : 3

Important thinking methods ： The sliding window , Traversal string , The left end position defaults to 0, The right end also defaults to 0, Slide gradually from the right end to the right .

class Solution { 
    
public:
    // Right end - Left side +1 Is the length of the string , The elements in the hash table are split strings 
    // If you don't encounter characters in the hash table , Then add to the hash table and continue to move right 
    // If you encounter characters in the hash table , Delete the original characters and slide the left end to the right , Until it's time to