class Solution {
public:
ListNode* swapPairs(ListNode* head)
{
ListNode* dummyHead = new ListNode(0);
dummyHead->next = head;
ListNode* temp = dummyHead;
while (temp->next != nullptr && temp->next->next != nullptr)
{
ListNode* node1 = temp->next;
ListNode* node2 = temp->next->next;
temp->next = node2;
node1->next = node2->next;
node2->next = node1;
temp = node1;
}
return dummyHead->next;
}
};