题解 | #链表内指定区间反转#

struct ListNode* reverseBetween(struct ListNode* head, int m, int n ) {
    if(m==n){
        return head;
    }
    // else
    struct ListNode* p;
    p = head;
    int  count = 1;
    while(p->next!=NULL && count<m){
        p = p->next;
        count++;
    }
    struct ListNode* p1;
    p1 = head;
    if(m!=1){
        while(p1->next!=p){
            p1 = p1->next;
        }
    }
    // p停在m位置
    // printf("p->val: %d\n",p->val);

    struct ListNode* q;
    q = p;
    while(q->next!=NULL && count<n){
        q = q->next;
        count++;
    }
    // q停在n当前的位置
    // printf("q->val: %d\n",q->val);

    // sub
    struct ListNode* subp;
    subp = NULL;
    struct ListNode* subtail;
    struct ListNode* headp;
    headp = p;
    struct ListNode* temp;
    int flag = 0;
    while(headp != q->next){
        temp = (struct ListNode*)malloc(sizeof(struct ListNode));
        temp -> next = NULL;
        temp -> val = headp -> val;
        temp -> next = subp;
        if(flag == 0){
            temp -> next = q->next;
        }
        subp = temp;
        headp = headp -> next;
        flag++;
    }
    // output the sub list
    // printf("the sub list \n");
    // struct ListNode* psub;
    // psub = subp;
    // while(psub!=NULL){
         // printf("%d ", psub->val);
         // psub = psub->next;
    // }
    // printf("\n");
    if(m!=1){
        p1->next = temp;
        return head;
    }else{
        // p1 = temp;
        return temp;
    }
}