6.28 problem solving

Today, I brushed two questions in order on the button .

The first question is to reverse the linked list .

This is the topic ,

I used a traversal . Then two nodes and one node are used to record the next node . A node is used to record a node .  Then point the pointer of the node being traversed to the previous node . Then traverse to the last   You can reverse the pointers of all nodes .

 

  The specific code and comments are like this .

The second question is Longest substring without repeating characters .

The topic here is based on the idea of sliding window . If I want to add a letter that already has a repeating letter in the substring .  Then I have to remove the repeated characters and all the previous characters from this string before I can add this character into a string without any repeated characters , Then I used one vector Container to record the position of each character in the string . Then use this container to judge and update . The value in the new Victor container is updated every time a duplicate character is added . And then use max Function to find the maximum value in the traversal process .

The code and comments are here