Sort a linked list using insertion sort.
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 insertionSortList(ListNode head) { 14 // IMPORTANT: Please reset any member data you declared, as 15 // the same Solution instance will be reused for each test case. 16 ListNode header = new ListNode(-1); 17 header.next = null; 18 if(head == null) return header.next; 19 ListNode cur = head; 20 while(cur != null){ 21 ListNode tmp = header.next; 22 ListNode before = header; 23 while(tmp != null && tmp.val < cur.val){ 24 before = before.next; 25 tmp = tmp.next; 26 } 27 before.next = cur; 28 ListNode a = cur.next; 29 cur.next = tmp; 30 cur = a; 31 } 32 return header.next; 33 } 34 }
第二遍：
1 public class Solution { 2 public ListNode insertionSortList(ListNode head) { 3 // IMPORTANT: Please reset any member data you declared, as 4 // the same Solution instance will be reused for each test case. 5 if(head == null) return head; 6 ListNode header = new ListNode(-1); 7 ListNode cur = head, newbefore = header; 8 while(cur != null){ 9 newbefore = header; 10 while(newbefore.next != null && newbefore.next.val < cur.val){ 11 newbefore = newbefore.next; 12 } 13 ListNode newcur = newbefore.next; 14 newbefore.next = cur; 15 ListNode tmp = cur.next; 16 cur.next = newcur; 17 cur = tmp; 18 } 19 return header.next; 20 } 21 }