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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct DoublyLinkedListNode {
  5.     int data;
  6.     DoublyLinkedListNode* next;
  7.     DoublyLinkedListNode* prev;
  8.  
  9.     DoublyLinkedListNode(int val) {
  10.         data = val;
  11.         next = nullptr;
  12.         prev = nullptr;
  13.     }
  14. };
  15.  
  16. DoublyLinkedListNode* reverse(DoublyLinkedListNode* head) {
  17.     DoublyLinkedListNode* current = head;
  18.     DoublyLinkedListNode* newHead = nullptr;
  19.  
  20.     while (current) {
  21.         swap(current->next, current->prev);
  22.         newHead = current;
  23.         current = current->prev;
  24.     }
  25.  
  26.     return newHead;
  27. }
  28.  
  29. void printList(DoublyLinkedListNode* head) {
  30.     while (head) {
  31.         cout << head->data << " ";
  32.         head = head->next;
  33.     }
  34.     cout << endl;
  35. }
  36.  
  37. int main() {
  38.     DoublyLinkedListNode* head = new DoublyLinkedListNode(10);
  39.     head->next = new DoublyLinkedListNode(20);
  40.     head->next->prev = head;
  41.     head->next->next = new DoublyLinkedListNode(30);
  42.     head->next->next->prev = head->next;
  43.  
  44.     head = reverse(head);
  45.     printList(head);
  46.  
  47.     return 0;
  48. }
  49.  
Success #stdin #stdout 0.01s 5288KB
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30 20 10
https://ideone.com/QZQLQ3
language:
C++ (gcc 8.3)
created:
5 days ago
visibility:
public

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