algorithm/[25]K 个一组翻转链表.java at master · Ada0910/algorithm

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//leetcode submit region begin(Prohibit modification and deletion)

/**

* Definition for singly-linked list.

* public class ListNode {

* int val;

* ListNode next;

* ListNode() {}

* ListNode(int val) { this.val = val; }

* ListNode(int val, ListNode next) { this.val = val; this.next = next; }

* }

class Solution {

public ListNode reverseKGroup(ListNode head, int k) {

//base case

if (head == null ) {

return null;

}

ListNode a = head;

ListNode b = head;

//k的数值大于链表的长度,则不需要反转

for (int i = 0; i < k; i++) {

if(b==null){

return head;

}

b = b.next;

}

ListNode temp = reverse(a, b);

a.next = reverseKGroup(b, k);

return temp;

}

//反转整个链表a到b的链表，返回链表的头结点

ListNode reverse(ListNode a, ListNode b) {

ListNode pre = null;

ListNode nxt = a;

ListNode cur = a;

while (cur != b) {

nxt = cur.next;

cur.next = pre;

pre = cur;

cur = nxt;

}

return pre;

}

//leetcode submit region end(Prohibit modification and deletion)

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[25]K 个一组翻转链表.java

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[25]K 个一组翻转链表.java

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