在O(1)时间复杂度删除链表节点

/**
 * Definition for ListNode.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int val) {
 *         this.val = val;
 *         this.next = null;
 *     }
 * }
 */ 
public class Solution {
    /**
     * @param node: the node in the list should be deleted
     * @return: nothing
     */
    public void deleteNode(ListNode node) {// write your code here
        if (node == null || node.next == null)
            return;
        ListNode next = node.next;
        node.val = next.val;
        node.next = next.next;
    }
}