25. Reverse Nodes in k-Group

k个一组反转链表

  1. public ListNode reverseKGroup(ListNode head, int k) {
  2.         ListNode hair = new ListNode(0);
  3.         hair.next = head;
  4.         ListNode pre = hair;
  6.         while (head != null) {
  7.             ListNode tail = pre;
  8.             // 查看剩余部分长度是否大于等于 k
  9.             for (int i = 0; i < k; ++i) {
  10.                 tail = tail.next;
  11.                 if (tail == null) {
  12.                     return hair.next;//
  13.                 }
  14.             }
  15.             ListNode nex = tail.next;
  16.             ListNode[] reverse = myReverse(head, tail);
  17.             head = reverse[0];
  18.             tail = reverse[1];
  19.             // 把子链表重新接回原链表
  20.             pre.next = head;
  21.             tail.next = nex;
  22.             pre = tail;
  23.             head = tail.next;
  24.         }
  26.         return hair.next;
  27.     }
  29.     public ListNode[] myReverse(ListNode head, ListNode tail) {
  30.         ListNode prev = tail.next;//
  31.         ListNode p = head;
  32.         while (prev != tail) {
  33.             ListNode nex = p.next;
  34.             p.next = prev;
  35.             prev = p;
  36.             p = nex;
  37.         }
  38.         return new ListNode[]{tail, head};
  39.     }
  41. 作者：LeetCode-Solution
  42. 链接：https://leetcode-cn.com/problems/reverse-nodes-in-k-group/solution/k-ge-yi-zu-fan-zhuan-lian-biao-by-leetcode-solutio/