题解 | #链表内指定区间反转#

/**
 * struct ListNode {
 *  int val;
 *  struct ListNode *next;
 * };
 */
/**
 * 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
 */
struct ListNode* reverseBetween(struct ListNode* head, int m, int n ) {
    // write code here
    int i = 1;
    struct ListNode* L, * s;
    struct ListNode* last, * last1;
    L = (struct ListNode*)malloc(sizeof(struct ListNode));
    L->next = NULL;
    last = L;
    while (head) {
        while (i < m && head != NULL) {
            s = (struct ListNode*)malloc(sizeof(struct ListNode));
            s->val = head->val;
            s->next = last->next;
            last->next = s;
            last = s;
            head = head->next;
            i++;
        }
        while (i >= m && i <= n && head != NULL) {
            s = (struct ListNode*)malloc(sizeof(struct ListNode));
            s->val = head->val;
            s->next = last->next;
            last->next = s;
            if (i == m) {
                last1 = s;
            }
            head = head->next;
            i++;
        }
        while (i > n && head != NULL) {
            s = (struct ListNode*)malloc(sizeof(struct ListNode));
            s->val = head->val;
            s->next = last1->next;
            last1->next = s;
            last1 = s;
            head = head->next;
            i++;
        }

    }
    return L->next;
}