题解 | #牛的品种排序IV#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    public ListNode sortCowsIV (ListNode head) {
        // write code here
        ListNode white = null;
        ListNode black = new ListNode(-1);
        ListNode cur = black;
        while(head != null){
            ListNode temp =  new ListNode(head.val);
            if(head.val == 0){
                cur.next = temp;
                cur = cur.next;
            }else{
                temp.next = white;
                white = temp;
            }
            head = head.next;
        }
        cur.next = white;
        return black.next;
    }
}