24.两两交换链表中的节点.cpp

/*
 * @lc app=leetcode.cn id=24 lang=cpp
 *
 * [24] 两两交换链表中的节点
 */

// @lc code=start
/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */

class Solution {
public:
    ListNode* swapPairs(ListNode* head) {
        ListNode* dummyHead = new ListNode(0);
        dummyHead->next = head;

        ListNode* curr = dummyHead;
        while(curr->next != nullptr && curr->next->next != nullptr)
        {
            ListNode* temp1 = curr->next;
            ListNode* temp2 = curr->next->next->next;
            curr->next = curr->next->next;
            curr->next->next = temp1;
            curr->next->next->next = temp2;

            curr = curr->next->next;
        }

        ListNode* resultHead = dummyHead->next;
        delete(dummyHead);
        return resultHead;
    }
};
// @lc code=end