LeetCode 328. 奇偶链表（注意成环）

奇偶链表

/**
 * 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* oddEvenList(ListNode* head) {
        if(!head || !head->next) return head;
        ListNode *p1 = head, *p2 = head->next;
        ListNode *move1 = p1, *move2 = p2;

        ListNode* cur = head->next->next;
        int i = 2;
        while(cur){
            if(i&1){
                move2->next = cur;
                move2 = cur;
            }else{
                move1->next = cur;
                move1 = cur; 
            }
            cur = cur->next;
            i++;

        }
        // 否则会成环的！
        move2->next = nullptr;
        move1->next = p2;
        return p1;
    }
};