美團筆試題：k鏈表翻轉

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k鏈表翻轉。給出一個鏈表和一個數k，比如鏈表1→2→3→4→5→6，k=2， 則翻轉後2→1→4→3→6→5，若k=3,翻轉後3→2→1→6→5→4，若k=4， 翻轉後4→3→2→1→5→6，用程序實現。 typedef struct node {     struct node *next;     int data; } node; void createList(node **head, int data) {     node *pre, *cur, *new;     pre = NULL;     cur = *head;     while (cur != NULL) {         pre = cur;         cur = cur->next;     }     new = (node *)malloc(sizeof(node));     new->data = data;     new->next = cur;     if (pre == NULL)     *head = new;     else     pre->next = new; } void printLink(node *head) {     while (head->next != NULL) {         printf("%d ", head->data);         head = head->next;     }     printf("%dn", head->data); } int linkLen(node *head) {     int len = 0;     while (head != NULL) {         len ++;         head = head->next;     }     return len; } node* reverseK(node *head, int k) {     int i, len, time, now;     len = linkLen(head);     if (len < k) {         return head;         } else {         time = len / k;     }     node *newhead, *prev, *next, *old, *tail;     for (now = 0, tail = NULL; now < time; now ++) {         old = head;         for (i = 0, prev = NULL; i < k; i ++) {             next = head->next;             head->next = prev;             prev = head;             head = next;         }         if (now == 0) {             newhead = prev;         }         old->next = head;         if (tail != NULL) {             tail->next = prev;         }         tail = old;     }     if (head != NULL) {         tail->next = head;     }     return newhead; } int main(void) {     int i, n, k, data;     node *head, *newhead;     while (scanf("%d %d", &n, &k) != EOF) {         for (i = 0, head = NULL; i < n; i ++) {             scanf("%d", &data);             createList(&head, data);         }         printLink(head);         newhead = reverseK(head, k);         printLink(newhead);     }     return 0; }