LeetCode 86 Partition List

 

需要两个dummy node来构造两个list：

一个是小于target的linked list

另一个是大于等于target的linked list

 

public class Solution {
  public ListNode partition(ListNode head, int target) {
    if (head == null) {
         return head; 
    }
    // Write your solution here
    ListNode less = new ListNode(0);
    ListNode large = new ListNode(0);
    ListNode lessTail = less;
    ListNode largeTail = large;
    
    ListNode cur = head;
    while (cur != null) {
      if (cur.value < target) {
           lessTail.next = cur;
        lessTail = lessTail.next;
      } else {
           largeTail.next = cur;
        largeTail = largeTail.next;
      }
      cur = cur.next;
    }
    lessTail.next = large.next;
    largeTail.next = null;
    return less.next;
  }
}