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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct SinglyLinkedListNode {
  5.     int data;
  6.     SinglyLinkedListNode* next;
  7.  
  8.     SinglyLinkedListNode(int val) {
  9.         data = val;
  10.         next = nullptr;
  11.     }
  12. };
  13.  
  14. SinglyLinkedListNode* mergeLists(SinglyLinkedListNode* head1, SinglyLinkedListNode* head2) {
  15.     if (!head1) return head2;
  16.     if (!head2) return head1;
  17.  
  18.     SinglyLinkedListNode* mergedHead = nullptr;
  19.  
  20.     if (head1->data < head2->data) {
  21.         mergedHead = head1;
  22.         head1 = head1->next;
  23.     } else {
  24.         mergedHead = head2;
  25.         head2 = head2->next;
  26.     }
  27.  
  28.     SinglyLinkedListNode* current = mergedHead;
  29.  
  30.     while (head1 && head2) {
  31.         if (head1->data < head2->data) {
  32.             current->next = head1;
  33.             head1 = head1->next;
  34.         } else {
  35.             current->next = head2;
  36.             head2 = head2->next;
  37.         }
  38.         current = current->next;
  39.     }
  40.  
  41.     if (head1) current->next = head1;
  42.     if (head2) current->next = head2;
  43.  
  44.     return mergedHead;
  45. }
  46.  
  47. void printList(SinglyLinkedListNode* head) {
  48.     while (head) {
  49.         cout << head->data << " ";
  50.         head = head->next;
  51.     }
  52.     cout << endl;
  53. }
  54.  
  55. int main() {
  56.     SinglyLinkedListNode* head1 = new SinglyLinkedListNode(1);
  57.     head1->next = new SinglyLinkedListNode(3);
  58.     head1->next->next = new SinglyLinkedListNode(5);
  59.  
  60.     SinglyLinkedListNode* head2 = new SinglyLinkedListNode(2);
  61.     head2->next = new SinglyLinkedListNode(4);
  62.     head2->next->next = new SinglyLinkedListNode(6);
  63.  
  64.     SinglyLinkedListNode* merged = mergeLists(head1, head2);
  65.     printList(merged);
  66.  
  67.     return 0;
  68. }
  69.  
Success #stdin #stdout 0s 5316KB
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https://ideone.com/C5fAm5
language:
C++ (gcc 8.3)
created:
21 days ago
visibility:
public

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