题解 | #链表内指定区间反转#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

class Solution {
public:
    /**
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode类
     */
    ListNode* reverseBetween(ListNode* head, int m, int n) {
        ListNode* tmp = new ListNode(0);
        tmp->next = head;
        ListNode* vnode = tmp;

        for (int i = 0; i < m-1; i++) {
            vnode = vnode->next;
        }
        
        ListNode* curr = vnode->next;
        int count = 1;
        while (curr != nullptr && count <= n-m) {
            // 交换vnode->next与curr
            ListNode* tmp = vnode->next;
            vnode->next = curr->next;
            curr->next = curr->next->next;
            vnode->next->next = tmp;
            // curr = curr->next;
            // cout << vnode->next->val << " " << vnode->next->next->val << endl;
            count++;
        }

        if (m == 1)
            return tmp->next;
        else
            return head;
    }
};

反转链表代码模板：

当前：vp->p2->p1->p3；curr=p1；

反转后：vp->p3->p2->p1；curr=p1；

代码：

while (curr->next != nullprt) {

tmp=vp->next；

vp->next = curr->next；

curr->next=cur->next->next；

vp->next->next=tmp；

}