链表内指定区间反转 C++
链表内指定区间反转
https://www.nowcoder.com/practice/b58434e200a648c589ca2063f1faf58c
/** * struct ListNode { * int val; * struct ListNode *next; * ListNode(int x) : val(x), next(nullptr) {} * }; */ class Solution { public: /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @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) { // write code here ListNode* Cur = head; ListNode* Next = nullptr; ListNode* Nodem = head; ListNode* Noden = head; //保存m和n原位置的地址 for(int i = 0; i < m-1; i++) { Nodem = Nodem->next; } for(int i = 0; i < n; i++) { Noden = Noden->next; } //反转区间链表 Cur = Nodem; ListNode* Pre = Noden; for(int i = 0 ; i <= n-m ; i++){ Next = Cur->next; Cur->next = Pre; Pre = Cur; Cur = Next; } //三表相连接 if (m == 1) { return Pre; } Cur = head; for(int i = 1; i < m-1; i++) { Cur = Cur->next; } Cur->next = Pre; return head; } };