c语言-leetcode 0025-reverse-nodes-in-k-group.zip

#include <stdio.h> #include <stdlib.h> struct ListNode { int val; struct ListNode *next; }; static struct ListNode* reverseKGroup(struct ListNode* head, int k) { int len = 0; struct ListNode dummy; struct ListNode *prev = &dummy; dummy.next = head; for (; head != NULL; head = head->next) { if (++len % k == 0) { /* p always the original first one */ struct ListNode *p = prev->next; /* loop condition implicits the final state */ while (prev->next != head) { /* the new segment head */ struct ListNode *q = p->next; /* deletion */ p->next = q->next; /* insertion */ q->next = prev->next; prev->next = q; } /* For iteration */ prev = p; head = p; } } return dummy.next; } int main(int argc, char **argv) { int i; struct ListNode *p, *prev, dummy, *list; dummy.next = NULL; prev = &dummy; for (i = 2; i < argc; i++) { p = malloc(sizeof(*p)); int n = atoi(argv[i]); printf("%d ", n); p->val = n; p->next = NULL; prev->next = p; prev = p; } putchar('\n'); list = reverseKGroup(dummy.next, atoi(argv[1])); for (p = list; p != NULL; p = p->next) { printf("%d ", p->val); } putchar('\n'); return 0; }