leetcode -- Reverse Nodes in k-Group
k个元素一组指针反转
函数调用问题！！！！
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * int val; 5 * ListNode next; 6 * ListNode(int x) { 7 * val = x; 8 * next = null; 9 * } 10 * } 11 */ 12 public class Solution { 13 public ListNode reverseKGroup(ListNode head, int k) { 14 // Start typing your Java solution below 15 // DO NOT write main() function 16 17 if(head == null || k == 1) 18 return head; 19 20 int len = 0; 21 ListNode p = head; 22 while(p != null){ 23 p = p.next; 24 len ++; 25 } 26 27 ListNode safeG = new ListNode(-1); 28 safeG.next = head; 29 ListNode pre = safeG, cur = head, post = head.next; 30 31 int m = len / k; 32 for(int i = 0; i < m; i++){ 33 post = cur.next; 34 //reverse(pre, cur, post, k); 35 int j = 0; 36 while(post != null){ 37 ListNode tmp = post.next; 38 post.next = cur; 39 cur = post; 40 post = tmp; 41 j ++; 42 if(j == k - 1) 43 break; 44 } 45 ListNode tmp = pre.next; 46 pre.next = cur; 47 tmp.next = post; 48 pre = tmp; 49 cur = pre.next; 50 51 } 52 53 return safeG.next; 54 55 } 56 57 public void reverse(ListNode pre, ListNode cur, ListNode post, int k){ 58 int i = 0; 59 while(post != null){ 60 ListNode tmp = post.next; 61 post.next = cur; 62 cur = post; 63 post = tmp; 64 i ++; 65 if(i == k - 1) 66 break; 67 } 68 } 69 70 }
