0219. Insert Node in Sorted Lin

我的方法：看了下面的解答我的解答再也不想看了。

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */

public class Solution {
    /**
     * @param head: The head of linked list.
     * @param val: An integer.
     * @return: The head of new linked list.
     */
    public ListNode insertNode(ListNode head, int val) {
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        head = dummy;
        ListNode inode = new ListNode(val);
        while(head.next!=null){
            if(val < dummy.next.val){
                ListNode tmp = dummy.next;
                dummy.next = inode;
                inode.next = tmp;
                return dummy.next;
            }else if(head.val <= val && val <=head.next.val){
                inode.next = head.next;
                head.next = inode;
                return dummy.next;
            }else{
                head = head.next;
            }
        }

        head.next = inode;
        inode.next=null;

        return dummy.next;
    }
}

九章解答

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param head: The head of linked list.
     * @param val: an integer
     * @return: The head of new linked list
     */
    public ListNode insertNode(ListNode head, int val) { 
        ListNode node = new ListNode(val);
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        head = dummy;
        
        // find the last element <= val
        while (head.next != null && head.next.val <= val) {
            head = head.next;
        }
        node.next = head.next;
        head.next = node;
        
        return dummy.next;
    }  
}