package algorithms; /** * @Auther: Jesper * @Date: 2019/2/13 15:42 * @Description: 单链表的快排 * * 我们只需要两个指针p1和p2，这两个指针均往next方向移动，移动的过程中保持p1之前的key都小于选定的key，p1和p2之间的key都大于选定的key，那么当p2走到末尾时交换p1与key值便完成了一次切分。 */ public class QuickSortList { class ListNode { ListNode next; int val; } public ListNode sortList(ListNode head){ //采用快速排序 quickSort(head, null); return head; } public static void quickSort(ListNode head, ListNode end){ if (head != end){ ListNode node = partion(head, end); quickSort(head, node); quickSort(node.next, end); } } public static ListNode partion(ListNode head, ListNode end){ ListNode p1 = head, p2 = head.next; //走到末尾才停 while (p2 != end){ //大于key值时，p1向前走一步，交换p1与p2的值 if (p2.val < head.val){ p1 = p1.next; int temp = p1.val; p1.val = p2.val; p2.val = temp; } p2 = p2.next; } //当有序时，不交换p1和key值 if (p1 != head){ int temp = p1.val; p1.val = head.val; head.val = temp; } return p1; } }